--- a/cwvreg.py	Tue Mar 10 19:36:21 2009 +0100
+++ b/cwvreg.py	Wed Mar 11 11:01:52 2009 +0100
@@ -30,6 +30,9 @@
                 return sorted(impl.expected_ifaces)
         except AttributeError:
             pass # old-style vobject classes with no accepts_interfaces
+        except:
+            print 'bad selector %s on %s' % (obj.__select__, obj)
+            raise
         return ()
 
 def expand_parent_classes(iface):