diff --git a/pitfall/pitfall/parse.rkt b/pitfall/pitfall/parse.rkt
index fcbdefee..d1e7cb40 100644
--- a/pitfall/pitfall/parse.rkt
+++ b/pitfall/pitfall/parse.rkt
@@ -75,7 +75,7 @@
   (define data (string->bytes/utf-8 str))
   (when (not (equal? (hash-ref (co-dict-dict dict) 'Length) (bytes-length data)))
     (raise-argument-error 'pf-stream
-                          (format "~a bytes of data" (hash-ref dict 'Length))
+                          (format "~a bytes of data" (hash-ref (co-dict-dict dict) 'Length))
                           (format "~a = ~v" (bytes-length data) data)))
   (co-stream dict data))
 
diff --git a/pitfall/pitfall/parser.rkt b/pitfall/pitfall/parser.rkt
index 4d7ff176..5cb1e395 100644
--- a/pitfall/pitfall/parser.rkt
+++ b/pitfall/pitfall/parser.rkt
@@ -1,6 +1,6 @@
 #lang brag
 
-pf-program : pf-header pf-object*
+pf-program : [pf-header] pf-object*
 pf-header : PDF-HEADER
 @pf-object : pf-null | CHAR | BOOLEAN | INT | REAL | pf-name | pf-string | pf-array | pf-dict | pf-stream | pf-indirect-object | pf-indirect-object-ref | pf-comment
 @pf-null : NULL