bug: the schema oid can't be located, please refresh all schemas

pgadmin version: 1.8.1
pgsql version: 8.3.rc1
os: windows 2003


when viewing a particular table with a (fts) trigger, pgAdmin gives the 
following error popup:

"missing information:
the schema oid can't be located, please refresh all schemas!"

refreshing the schemas as suggested by the error message doesn't help.

the offending trigger seems to be:

CREATE TRIGGER posts_fts_update  BEFORE INSERT OR UPDATE  ON forum.posts  FOR EACH ROW  EXECUTE PROCEDURE
forum.tsvector_update_trigger('p_fts',
 
'pg_catalog.german', 'p_msg_clean');

with the corresponding procedure:

CREATE OR REPLACE FUNCTION forum.tsvector_update_trigger()  RETURNS trigger AS
'tsvector_update_trigger_byid'  LANGUAGE 'internal' VOLATILE  COST 1;
ALTER FUNCTION forum.tsvector_update_trigger() OWNER TO postgres;
COMMENT ON FUNCTION forum.tsvector_update_trigger() IS 'trigger for 
automatic update of tsvector column';

not sure if its 8.3 or pgAdmin/FTS related. the pgsql log shows no 
additional error/warning...

regards,
thomas