diff --git a/src/mzscheme/src/error.c b/src/mzscheme/src/error.c
index 37cd30c99a..f1c73a0c2e 100644
--- a/src/mzscheme/src/error.c
+++ b/src/mzscheme/src/error.c
@@ -2277,7 +2277,7 @@ void scheme_write_proc_context(Scheme_Object *port, int print_width,
       scheme_display_w_max(line, port, print_width);
       scheme_write_byte_string(":", 1, port);
       scheme_display_w_max(col, port, print_width);
-    } else {
+    } else if (pos && SCHEME_TRUEP(pos)) {
       /* Position */
       scheme_write_byte_string("::", 2, port);
       scheme_display_w_max(pos, port, print_width);
diff --git a/src/mzscheme/src/fun.c b/src/mzscheme/src/fun.c
index c8cac95cc0..899ff9e9e2 100644
--- a/src/mzscheme/src/fun.c
+++ b/src/mzscheme/src/fun.c
@@ -7182,6 +7182,24 @@ scheme_get_stack_trace(Scheme_Object *mark_set)
 	name = scheme_make_pair(scheme_false, loc);
       else
 	name = scheme_make_pair(SCHEME_VEC_ELS(name)[0], loc);
+    } else if (SCHEME_PAIRP(name)
+               && SAME_TYPE(SCHEME_TYPE(SCHEME_CAR(name)), 
+                            scheme_resolved_module_path_type)) {
+      /* a resolved module path means that we're running a module body */
+      const char *what;
+
+      if (SCHEME_FALSEP(SCHEME_CDR(name)))
+        what = "[traversing imports]";
+      else
+        what = "[running body]";
+
+      name = SCHEME_CAR(name);
+      name = SCHEME_PTR_VAL(name);
+      loc = scheme_make_location(name, scheme_false, 
+                                 scheme_false, scheme_false, scheme_false);
+
+      name = scheme_intern_symbol(what);
+      name = scheme_make_pair(name, loc);
     } else {
       name = scheme_make_pair(name, scheme_false);
     }
diff --git a/src/mzscheme/src/jit.c b/src/mzscheme/src/jit.c
index a4ec8e418e..4044bba1a5 100644
--- a/src/mzscheme/src/jit.c
+++ b/src/mzscheme/src/jit.c
@@ -147,6 +147,7 @@ static void *struct_proc_extract_code;
 static void *bad_app_vals_target;
 static void *app_values_slow_code, *app_values_multi_slow_code, *app_values_tail_slow_code;
 static void *finish_tail_call_code, *finish_tail_call_fixup_code;
+static void *module_run_start_code, *module_start_start_code;
 
 typedef struct {
   MZTAG_IF_REQUIRED
@@ -8432,6 +8433,75 @@ static int do_generate_more_common(mz_jit_state *jitter, void *_data)
     }
   }
 
+  /* *** module_run_start_code *** */
+  /* Pushes a module name onto the stack for stack traces. */
+  {
+    void *code_end;
+    int in;
+    
+    module_run_start_code = jit_get_ip().ptr;
+    jit_prolog(3);
+    in = jit_arg_p();
+    jit_getarg_p(JIT_R0, in); /* menv */
+    in = jit_arg_p();
+    jit_getarg_p(JIT_R1, in); /* env */
+    in = jit_arg_p();
+    jit_getarg_p(JIT_R2, in); /* &name */
+    CHECK_LIMIT();
+
+    /* Store the name where we can find it */
+    mz_push_locals();
+    mz_set_local_p(JIT_R2, JIT_LOCAL2);
+
+    jit_prepare(2);
+    jit_pusharg_p(JIT_R1);
+    jit_pusharg_p(JIT_R0);
+    (void)mz_finish(scheme_module_run_finish);
+    CHECK_LIMIT();
+    jit_retval(JIT_R0);
+    mz_pop_locals();
+    jit_ret();
+    CHECK_LIMIT();
+
+    if (jitter->retain_start) {
+      code_end = jit_get_ip().ptr;
+      add_symbol((unsigned long)module_run_start_code, (unsigned long)code_end - 1, scheme_eof, 0);
+    }
+  }
+
+  /* *** module_start_start_code *** */
+  /* Pushes a module name onto the stack for stack traces. */
+  {
+    void *code_end;
+    int in;
+    
+    module_start_start_code = jit_get_ip().ptr;
+    jit_prolog(2);
+    in = jit_arg_p();
+    jit_getarg_p(JIT_R0, in); /* a */
+    in = jit_arg_p();
+    jit_getarg_p(JIT_R1, in); /* &name */
+    CHECK_LIMIT();
+
+    /* Store the name where we can find it */
+    mz_push_locals();
+    mz_set_local_p(JIT_R1, JIT_LOCAL2);
+
+    jit_prepare(1);
+    jit_pusharg_p(JIT_R0);
+    (void)mz_finish(scheme_module_start_finish);
+    CHECK_LIMIT();
+    jit_retval(JIT_R0);
+    mz_pop_locals();
+    jit_ret();
+    CHECK_LIMIT();
+
+    if (jitter->retain_start) {
+      code_end = jit_get_ip().ptr;
+      add_symbol((unsigned long)module_start_start_code, (unsigned long)code_end - 1, scheme_eof, 0);
+    }
+  }
+
   return 1;
 }
 
@@ -9365,6 +9435,27 @@ Scheme_Object *scheme_native_stack_trace(void)
       }
 #endif
       name = find_symbol((unsigned long)q);
+    } else if (SCHEME_EOFP(name)) {
+      /* Stub (to mark start of running a module body, for example) */
+      /* JIT_LOCAL2 has the name to use */
+#ifdef MZ_USE_JIT_PPC
+      name = *(Scheme_Object **)((void **)p)[JIT_LOCAL2 >> JIT_LOG_WORD_SIZE];
+#endif
+#ifdef MZ_USE_JIT_I386
+      void *np;
+# ifdef MZ_USE_DWARF_LIBUNWIND
+      if (use_unw) {
+	np = (void *)unw_get_frame_pointer(&c);
+      } else
+# endif
+	np = *(void **)p;
+
+      if (STK_COMP((unsigned long)np, stack_end)
+	  && STK_COMP(stack_start, (unsigned long)np)) {
+        name = *(Scheme_Object **)((void **)np)[JIT_LOCAL2 >> JIT_LOG_WORD_SIZE];
+      } else
+        name = NULL;
+#endif
     }
 
     if (name && !SCHEME_NULLP(name)) { /* null is used to help unwind without a true name */
@@ -9374,8 +9465,7 @@ Scheme_Object *scheme_native_stack_trace(void)
       else
 	first = name;
       last = name;
-      if (set_next_push) {
-	stack_cache_stack[stack_cache_stack_pos].cache = name;
+      if (set_next_push) {	stack_cache_stack[stack_cache_stack_pos].cache = name;
 	set_next_push = 0;
       }
     }
@@ -9569,6 +9659,21 @@ static void release_native_code(void *fnlized, void *p)
 }
 #endif
 
+typedef void *(*Module_Run_Proc)(Scheme_Env *menv, Scheme_Env *env, Scheme_Object **name);
+typedef void *(*Module_Start_Proc)(struct Start_Module_Args *a, Scheme_Object **name);
+
+void *scheme_module_run_start(Scheme_Env *menv, Scheme_Env *env, Scheme_Object *name)
+{
+  Module_Run_Proc proc = (Module_Run_Proc)module_run_start_code;
+  return proc(menv, env, &name);
+}
+
+void *scheme_module_start_start(struct Start_Module_Args *a, Scheme_Object *name)
+{
+  Module_Start_Proc proc = (Module_Start_Proc)module_start_start_code;
+  return proc(a, &name);
+}
+
 /**********************************************************************/
 /*                           Precise GC                               */
 /**********************************************************************/
diff --git a/src/mzscheme/src/module.c b/src/mzscheme/src/module.c
index 3205df0239..8942caaa34 100644
--- a/src/mzscheme/src/module.c
+++ b/src/mzscheme/src/module.c
@@ -3863,6 +3863,44 @@ static void chain_start_module(Scheme_Env *menv, Scheme_Env *env, int eval_exp,
   }
 }
 
+typedef struct Start_Module_Args {
+  Scheme_Env *menv;
+  Scheme_Env *env;
+  int eval_exp;
+  int eval_run;
+  long base_phase;
+  Scheme_Object *cycle_list;
+  Scheme_Object *syntax_idx;
+} Start_Module_Args;
+
+static void chain_start_module_w_push(Scheme_Env *menv, Scheme_Env *env, int eval_exp, int eval_run, 
+                                      long base_phase, Scheme_Object *cycle_list, Scheme_Object *syntax_idx)
+{
+  Start_Module_Args a;
+  
+  a.menv = menv;
+  a.env = env;
+  a.eval_exp = eval_exp;
+  a.eval_run = eval_run;
+  a.base_phase = base_phase;
+  a.cycle_list = cycle_list;
+  a.syntax_idx = syntax_idx;
+
+#ifdef MZ_USE_JIT
+  (void)scheme_module_start_start(&a, scheme_make_pair(menv->module->modname, scheme_false));
+#else
+  (void)scheme_module_start_finish(&a);
+#endif
+}
+
+void *scheme_module_start_finish(struct Start_Module_Args *a)
+{
+  chain_start_module(a->menv, a->env,
+                     a->eval_exp, a->eval_run, a->base_phase,
+                     a->cycle_list, a->syntax_idx);
+  return NULL;
+}
+
 static Scheme_Env *instantiate_module(Scheme_Module *m, Scheme_Env *env, int restart, Scheme_Object *syntax_idx)
 {
   Scheme_Env *menv;
@@ -4074,8 +4112,8 @@ static void should_run_for_compile(Scheme_Env *menv)
 }
 
 static void start_module(Scheme_Module *m, Scheme_Env *env, int restart, 
-			 Scheme_Object *syntax_idx, int eval_exp, int eval_run, long base_phase,
-			 Scheme_Object *cycle_list)
+                         Scheme_Object *syntax_idx, int eval_exp, int eval_run, long base_phase,
+                         Scheme_Object *cycle_list)
 /* eval_exp == -1 => make it ready, eval_exp == 1 => run exp-time, eval_exp = 0 => don't even make ready */
 {
   Scheme_Env *menv;
@@ -4113,7 +4151,7 @@ static void start_module(Scheme_Module *m, Scheme_Env *env, int restart,
     menv->did_starts = v;
   }
 
-  chain_start_module(menv, env, eval_exp, eval_run, base_phase, cycle_list, syntax_idx);
+  chain_start_module_w_push(menv, env, eval_exp, eval_run, base_phase, cycle_list, syntax_idx);
 
   if (restart) {
     if (menv->rename_set_ready) {
@@ -4223,6 +4261,15 @@ static void *eval_module_body_k(void)
 #endif
 
 static void eval_module_body(Scheme_Env *menv, Scheme_Env *env)
+{
+#ifdef MZ_USE_JIT
+  (void)scheme_module_run_start(menv, env, scheme_make_pair(menv->module->modname, scheme_true));
+#else
+  (void)scheme_module_run_finish(menv, env);
+#endif
+}
+
+void *scheme_module_run_finish(Scheme_Env *menv, Scheme_Env *env)
 {
   Scheme_Thread *p;
   Scheme_Module *m = menv->module;
@@ -4244,7 +4291,7 @@ static void eval_module_body(Scheme_Env *menv, Scheme_Env *env)
     p->ku.k.p1 = menv;
     p->ku.k.p2 = env;
     (void)scheme_enlarge_runstack(depth, eval_module_body_k);
-    return;
+    return NULL;
   }
 
   LOG_START_RUN(menv->module);
@@ -4309,6 +4356,8 @@ static void eval_module_body(Scheme_Env *menv, Scheme_Env *env)
   }
 
   LOG_END_RUN(menv->module);
+
+  return NULL;
 }
 
 static void run_module(Scheme_Env *menv, int set_ns)
diff --git a/src/mzscheme/src/schpriv.h b/src/mzscheme/src/schpriv.h
index ae50325f25..b40d4f2abc 100644
--- a/src/mzscheme/src/schpriv.h
+++ b/src/mzscheme/src/schpriv.h
@@ -2351,6 +2351,15 @@ void scheme_finish_application(Scheme_App_Rec *app);
 Scheme_Object *scheme_jit_expr(Scheme_Object *);
 Scheme_Object *scheme_jit_closure(Scheme_Object *, Scheme_Object *context);
 
+struct Start_Module_Args;
+
+#ifdef MZ_USE_JIT
+void *scheme_module_run_start(Scheme_Env *menv, Scheme_Env *env, Scheme_Object *name);
+void *scheme_module_start_start(struct Start_Module_Args *a, Scheme_Object *name);
+#endif
+void *scheme_module_run_finish(Scheme_Env *menv, Scheme_Env *env);
+void *scheme_module_start_finish(struct Start_Module_Args *a);
+
 Scheme_Object *scheme_build_closure_name(Scheme_Object *code, Scheme_Compile_Info *rec, int drec);
 
 #define SCHEME_SYNTAX(obj)     SCHEME_PTR1_VAL(obj)
diff --git a/src/mzscheme/src/struct.c b/src/mzscheme/src/struct.c
index d15c8860de..ac4cb1b1e2 100644
--- a/src/mzscheme/src/struct.c
+++ b/src/mzscheme/src/struct.c
@@ -1238,7 +1238,7 @@ static Scheme_Object *check_equal_property_value_ok(int argc, Scheme_Object *arg
 
   if (!v) {
     scheme_arg_mismatch("guard-for-prop:equal+hash",
-                        "expected a list containing a recursive-equality procedure (arity 2)"
+                        "expected a list containing a recursive-equality procedure (arity 3)"
                         " and two recursive hash-code procedures (arity 2), given: ",
                         argv[0]);
   }
diff --git a/src/mzscheme/src/syntax.c b/src/mzscheme/src/syntax.c
index c2147ea69d..3f327eae92 100644
--- a/src/mzscheme/src/syntax.c
+++ b/src/mzscheme/src/syntax.c
@@ -5610,8 +5610,15 @@ static Scheme_Object *define_for_syntaxes_sfs(Scheme_Object *data, SFS_Info *inf
 static Scheme_Object *stx_val(Scheme_Object *name, Scheme_Object *_env)
 {
   Scheme_Env *env = (Scheme_Env *)_env;
+  Scheme_Object *r;
+
+  r = scheme_tl_id_sym(env, name, NULL, 2, NULL, NULL);
+    printf("%s %s %p\n", 
+           scheme_write_to_string(name, NULL),
+           scheme_write_to_string(r, NULL),
+           env);
+    return r;
 
-  return scheme_tl_id_sym(env, name, NULL, 2, NULL, NULL);
 }
 
 static Scheme_Object *