diff --git a/parser/parse-bytecode-5.1.1.rkt b/parser/parse-bytecode-5.1.1.rkt
index 4ae0a90..03cf9d8 100644
--- a/parser/parse-bytecode-5.1.1.rkt
+++ b/parser/parse-bytecode-5.1.1.rkt
@@ -6,7 +6,7 @@
 
 (version-case
   [(and (version<= "5.1.1" (version))
-        (version< (version) "5.1.2"))
+        (version< (version) "5.1.1.900"))
 
 
    ;; Parsing Racket 5.1.1 bytecode structures into our own structures.
diff --git a/parser/parse-bytecode-5.1.2.rkt b/parser/parse-bytecode-5.1.2.rkt
index 1ab6e45..a5b943c 100644
--- a/parser/parse-bytecode-5.1.2.rkt
+++ b/parser/parse-bytecode-5.1.2.rkt
@@ -6,7 +6,7 @@
 
 
 (version-case
-  [(version<= "5.1.2" (version))
+  [(version<= "5.1.1.900" (version))
 
 
 
@@ -443,7 +443,7 @@
              (for/list ([v provided-values])
                        (match v
                          [(struct provided (name src src-name nom-mod
-                                                 src-phase protected? insp))
+                                                 src-phase protected?))
                           (make-ModuleProvide src-name name (subresolver src))])))]
           [else
            (loop (rest provides))]))))
@@ -511,7 +511,7 @@
 
    (define (parse-lam expr entry-point-label)
      (match expr
-       [(struct lam (name flags num-params param-types rest? closure-map closure-types max-let-depth body))
+       [(struct lam (name flags num-params param-types rest? closure-map closure-types toplevel-map max-let-depth body))
         (let ([lam-name (extract-lam-name name)])
           (make-Lam lam-name 
                     num-params 
@@ -532,7 +532,7 @@
           (cond
            [(hash-has-key? seen gen-id)
             (match code
-              [(struct lam (name flags num-params param-types rest? closure-map closure-types max-let-depth body))
+              [(struct lam (name flags num-params param-types rest? closure-map closure-types toplevel-map max-let-depth body))
                (let ([lam-name (extract-lam-name name)])
                  (make-EmptyClosureReference lam-name 
                                              num-params 
@@ -720,7 +720,7 @@
 
    (define (parse-varref expr)
      (match expr
-       [(struct varref (toplevel))
+       [(struct varref (toplevel dummy))
         (make-VariableReference (parse-toplevel toplevel))]))
 
    (define (parse-assign expr)
diff --git a/parser/parse-bytecode.rkt b/parser/parse-bytecode.rkt
index ab7771c..f491917 100644
--- a/parser/parse-bytecode.rkt
+++ b/parser/parse-bytecode.rkt
@@ -7,17 +7,17 @@
 
 (version-case
   [(and (version<= "5.1.1" (version))
-        (version< (version) "5.1.2"))
+        (version< (version) "5.1.1.900"))
    (begin
      (log-debug "Using 5.1.1 bytecode parser")
      (require "parse-bytecode-5.1.1.rkt")
      (provide (except-out (all-from-out "parse-bytecode-5.1.1.rkt")
                           parse-bytecode)))]
-  [(version<= "5.1.2" (version))
+  [(version<= "5.1.1.900" (version))
    (begin
      (log-debug "Using 5.1.2 bytecode parser")
      (require "parse-bytecode-5.1.2.rkt")
-     (provide (except-out (all-from-out "parse-bytecode-5.1.1.rkt")
+     (provide (except-out (all-from-out "parse-bytecode-5.1.2.rkt")
                           parse-bytecode)))]
   [else
    (error 'parse-bytecode "Whalesong doesn't have a compatible parser for Racket ~a" (version))])