dangling lock information?

I'm currently testing pgAdmin support for slony, on pgsql CVS HEAD, and 
encounter strange problems from time to time.
After dropping and recreating the slony schema, all changes committed 
and all backends in <IDLE> state, I'm getting
"relation with OID xxx does not exist" when I'm trying to add a path. 
This seems to be triggered inside slony functions when a   LOCK _test.pg_config IN EXCLUSIVE MODE
is performed.
The problem is gone as soon as I close the connection I've been using 
for prior schema changes, and use a fresh connection.

Does this description ring a bell for somebody?

Regards,
Andreas