Index: blockreference.module
===================================================================
--- blockreference.module	(revision 87)
+++ blockreference.module	(working copy)
@@ -658,10 +658,12 @@
 
   // Handle related modules - this will be used in extra query conditions.
   if (isset($field['referenceable_modules'])) {
-    foreach ($field['referenceable_modules'] as $related_module) {
-      if ($related_module !== 0 && $related_module != '0') {
-        $related_modules[] = " b.module = '%s'";
-        $args[] = $related_module;
+    if(!empty($field['referenceable_modules'])){
+      foreach ($field['referenceable_modules'] as $related_module) {
+        if ($related_module !== 0 && $related_module != '0') {
+          $related_modules[] = " b.module = '%s'";
+          $args[] = $related_module;
+        }
       }
     }
   }