diff --git a/mozilla/netwerk/test/httpserver/httpd.js b/mozilla/netwerk/test/httpserver/httpd.js
index 6e702a3e8aa..e7466fc632c 100644
--- a/mozilla/netwerk/test/httpserver/httpd.js
+++ b/mozilla/netwerk/test/httpserver/httpd.js
@@ -441,7 +441,7 @@ nsHttpServer.prototype =
   //
   registerFile: function(path, file)
   {
-    if (!file.exists() || lf.isDirectory())
+    if (!file.exists() || file.isDirectory())
       throw Cr.NS_ERROR_INVALID_ARG;
 
     this._handler.registerFile(path, file);
@@ -1569,7 +1569,10 @@ ServerHandler.prototype =
         response.recycle();
 
         if (!(e instanceof HttpError))
+        {
+          dumpn("*** unexpected error: e == " + e);
           throw HTTP_500;
+        }
         if (e.code != 404)
           throw e;
 
@@ -1620,6 +1623,7 @@ ServerHandler.prototype =
     dumpn("*** registering '" + path + "' as mapping to " + file.path);
     file = file.clone();
 
+    var self = this;
     this._overridePaths[path] =
       function(metadata, response)
       {
@@ -1627,7 +1631,7 @@ ServerHandler.prototype =
           throw HTTP_404;
 
         response.setStatusLine(metadata.httpVersion, 200, "OK");
-        this._writeFileResponse(file, response);
+        self._writeFileResponse(file, response);
         maybeAddHeaders(file, metadata, response);
       };
   },
diff --git a/mozilla/netwerk/test/httpserver/test/test_registerfile.js b/mozilla/netwerk/test/httpserver/test/test_registerfile.js
new file mode 100644
index 00000000000..f5889fff870
--- /dev/null
+++ b/mozilla/netwerk/test/httpserver/test/test_registerfile.js
@@ -0,0 +1,82 @@
+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is MozJSHTTP code.
+ *
+ * The Initial Developer of the Original Code is
+ * Jeff Walden <jwalden+code@mit.edu>.
+ * Portions created by the Initial Developer are Copyright (C) 2007
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+// tests the registerFile API
+
+const BASE = "http://localhost:4444";
+
+function isException(e, code)
+{
+  if (e !== code && e.result !== code)
+    do_throw("unexpected error: " + e);
+}
+
+var file = do_get_file("netwerk/test/httpserver/test/test_registerfile.js");
+
+function onStart(ch, cx)
+{
+  do_check_eq(ch.responseStatus, 200);
+}
+
+function onStop(ch, cx, status, data)
+{
+  // not sufficient for equality, but not likely to be wrong!
+  do_check_eq(data.length, file.fileSize);
+}
+
+var test = new Test(BASE + "/foo", null, onStart, onStop);
+
+function run_test()
+{
+  var srv = createServer();
+
+  try
+  {
+    srv.registerFile("/foo", do_get_file("netwerk/test/httpserver/"));
+    throw "registerFile succeeded!";
+  }
+  catch (e)
+  {
+    isException(e, Cr.NS_ERROR_INVALID_ARG);
+  }
+
+  srv.registerFile("/foo", file);
+  srv.start(4444);
+
+  runHttpTests([test], function() { srv.stop(); });
+}