diff --git a/collects/mzlib/port.ss b/collects/mzlib/port.ss
index 17441c2..16a04f0 100644
--- a/collects/mzlib/port.ss
+++ b/collects/mzlib/port.ss
@@ -1627,7 +1627,7 @@
                         (begin
                           (when (> len2 (bytes-length out-bytes))
                             (raise-insane-decoding-length))
-                          (bytes-copy out-bytes 0 s2 start2 (+ start2 len2))
+                          (bytes-copy! out-bytes 0 s2 start2 (+ start2 len2))
                           (set! out-start 0)
                           (set! out-end len2)
                           used))]
diff --git a/collects/net/url-unit.ss b/collects/net/url-unit.ss
index a23a674..986012c 100644
--- a/collects/net/url-unit.ss
+++ b/collects/net/url-unit.ss
@@ -154,7 +154,7 @@
         [(pair? strs)
          (apply build-path (string->path/win (car strs))
                 (map string->path-element/same (cdr strs)))]
-        [else (build-path)]) ; error
+        [else (error 'file://->path "no path elements: ~e" url)])
       (let ([elems (map string->path-element/same strs)])
         (if (url-path-absolute? url)
           (apply build-path (bytes->path #"/" 'unix) elems)
diff --git a/collects/scheme/private/old-procs.ss b/collects/scheme/private/old-procs.ss
index e3bbb9f..061fc5b 100644
--- a/collects/scheme/private/old-procs.ss
+++ b/collects/scheme/private/old-procs.ss
@@ -54,21 +54,21 @@
               (make-hash)
               (if (eq? a 'weak)
                   (make-weak-hasheq)
-                  (raise-mismatch-error "make-hash-table: bad argument: " a)))]
+                  (raise-mismatch-error 'make-hash-table "bad argument: " a)))]
      [(a b) (if (or (and (eq? a 'equal)
                          (eq? b 'weak))
                     (and (eq? a 'weak)
                          (eq? b 'equal)))
                 (make-weak-hash)
-                (raise-mismatch-error "make-hash-table: bad arguments: " (list a b)))]))
+                (raise-mismatch-error 'make-hash-table "bad arguments: " (list a b)))]))
 
   (define make-immutable-hash-table
     (case-lambda
      [(l) (make-immutable-hasheq l)]
      [(l a) (if (eq? a 'equal)
                 (make-immutable-hash l)
-                (raise-mismatch-error "make-immutable-hash-table: bad argument: " a))]))
-
+                (raise-mismatch-error 'make-immutable-hash-table "bad argument: " a))]))
+  
   (define hash-table?
     (case-lambda
      [(v) (hash? v)]
@@ -78,7 +78,7 @@
                 (if (eq? a 'weak)
                     (and (hash? v)
                          (hash-weak? v))
-                    (raise-mismatch-error "hash-table?: bad argument: " a)))]
+                    (raise-mismatch-error 'hash-table? "bad argument: " a)))]
      [(v a b) (if (or (and (eq? a 'equal)
                            (eq? b 'weak))
                       (and (eq? a 'weak)
@@ -86,4 +86,4 @@
                   (and (hash? v)
                        (not (hash-eq? v))
                        (hash-weak? v))
-                  (raise-mismatch-error "hash-table?: bad arguments: " (list a b)))])))
+                  (raise-mismatch-error 'hash-table? "bad arguments: " (list a b)))])))