diff --git a/src/mzscheme/src/error.c b/src/mzscheme/src/error.c
index b26170be14..35f971240c 100644
--- a/src/mzscheme/src/error.c
+++ b/src/mzscheme/src/error.c
@@ -1169,9 +1169,11 @@ void scheme_wrong_type(const char *name, const char *expected,
 
   if ((which < 0) || (argc == 1))
     scheme_raise_exn(MZEXN_FAIL_CONTRACT,
-		     "%s: expects %s of type <%s>; "
+		     "%s: expect%s %s of type <%s>; "
 		     "given %t",
-		     name, isress, expected, s, slen);
+		     name, 
+		     (which < 0) ? "ed" : "s",
+		     isress, expected, s, slen);
   else {
     char *other;
     long olen;
diff --git a/src/mzscheme/src/module.c b/src/mzscheme/src/module.c
index 75da9eda85..ebeacfb768 100644
--- a/src/mzscheme/src/module.c
+++ b/src/mzscheme/src/module.c
@@ -1804,6 +1804,11 @@ static Scheme_Object *_module_resolve(Scheme_Object *modidx, Scheme_Object *stx,
 
     name = scheme_apply(scheme_get_param(scheme_current_config(), MZCONFIG_CURRENT_MODULE_RESOLVER), 4, a);
     
+    if (!SCHEME_SYMBOLP(name)) {
+      a[0] = name;
+      scheme_wrong_type("module name resolver", "symbol", -1, -1, a);
+    }
+
     ((Scheme_Modidx *)modidx)->resolved = name;
   }