Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.776
diff -u -p -r1.776 common.inc
--- includes/common.inc	2 Jul 2008 19:36:52 -0000	1.776
+++ includes/common.inc	17 Jul 2008 10:29:13 -0000
@@ -435,6 +435,11 @@ function drupal_http_request($url, $head
 
   // 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;
+  }
 
   switch ($uri['scheme']) {
     case 'http':