Index: og_user_roles.module
===================================================================
--- og_user_roles.module	(revision 903)
+++ og_user_roles.module	(working copy)
@@ -504,12 +504,14 @@
   $rows = array();
 
   $i = 0;
-  foreach ($form['user_roles']['users'] as $user_form) {
-    $uid = $user_form['#value'];
+  if (is_array($form['user_roles']['users'])) {
+    foreach ($form['user_roles']['users'] as $user_form) {
+      $uid = $user_form['#value'];
 
-    if ($uid) {
-      $rows[$i][] = drupal_render($form['user_roles']['roles'][$uid]);
-      $i++;
+      if ($uid) {
+        $rows[$i][] = drupal_render($form['user_roles']['roles'][$uid]);
+        $i++;
+      }
     }
   }