And if you go fishing in pg_class for any of the oids, you don't find anything:
That is probably because you are connected in the wrong database. Once you connect to the database of interest, you don't even need to query pg_class, just cast relation attribute to regclass:
SELECT relation::regclass, ... FROM pg_locks WHERE database = (SELECT oid FROM pg_database WHERE datname = current_database());
Regards,
-- Matheus de Oliveira Analista de Banco de Dados Dextra Sistemas - MPS.Br nível F! www.dextra.com.br/postgres