--- a/server/msplanner.py	Mon Jun 15 18:28:44 2009 +0200
+++ b/server/msplanner.py	Mon Jun 15 18:30:27 2009 +0200
@@ -1374,6 +1374,8 @@
         try:
             res = self.visit_default(node, newroot, terms)[0]
         except:
+            # when a relation isn't supported, we should dereference potentially
+            # introduced variable refs
             for vref in self._pending_vrefs:
                 vref.unregister_reference()
             raise