Index: feeds/feeds_ui/feeds_ui.admin.inc
===================================================================
--- feeds/feeds_ui/feeds_ui.admin.inc	(revision 87)
+++ feeds/feeds_ui/feeds_ui.admin.inc	(working copy)
@@ -609,11 +609,13 @@
     }
   }
 
-  foreach ($form_state['values']['remove_flags'] as $k => $v) {
-    if ($v) {
-      unset($mappings[$k]);
-      // Keep our keys clean.
-      $mappings = array_values($mappings);
+  if (!empty($form_state['values']['remove_flags'])) {
+    foreach ($form_state['values']['remove_flags'] as $k => $v) {
+      if ($v) {
+        unset($mappings[$k]);
+        // Keep our keys clean.
+        $mappings = array_values($mappings);
+      }
     }
   }
   $processor->addConfig(array('mappings' => $mappings));