Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.781
diff -u -r1.781 common.inc
--- includes/common.inc	2 Aug 2008 19:01:02 -0000	1.781
+++ includes/common.inc	10 Aug 2008 16:15:26 -0000
@@ -436,6 +436,16 @@
   // Parse the URL and make sure we can handle the schema.
   $uri = parse_url($url);
 
+  if (!isset($uri['scheme'])) {
+    $result->error = 'missing schema';
+    return $result;
+  }
+
+  if (!isset($uri['host'])) {
+    $result->error = 'missing host';
+    return $result;
+  }
+
   switch ($uri['scheme']) {
     case 'http':
       $port = isset($uri['port']) ? $uri['port'] : 80;