--- grid.inc.orig	2010-10-18 02:20:54.000000000 -0500
+++ grid.inc	2010-11-16 11:24:23.430496900 -0600
@@ -360,6 +360,9 @@
     if (isset($value[$key]) && isset($options[$value[$key]])) {
       $return[] = $export_options['select_keys'] ? $value[$key] : $options[$value[$key]];
     }
+    else {
+      $return[] = '';
+    }
   }
   return $return;
 }