Contraint Trigger Permissions

I'm using PostgreSQL 7.3.6 and run into a permissions problem when a
particular constraint trigger is attempting to restore using
pg_restore.

Is there a good way to analyze what permissions are required for a
particular constraint trigger? I have a problem where it looks like a
contraint trigger does not have the necessary access to a table, but I
don't want to enable more permissions to that table than the trigger
requires.

Any assistance or pointers would be very much appreciated!