Hmmm...right.  Dave - the Schema Browser is working for Postgres and will list all tables that have RI checks on a given table, so poking around in the SB might help you figure out which tables might still have rows pointing to the entry being deleted.

(The SB doesn't work for Oracle due to some driver problems, I think(?)  I'm not sure but I've been informed it breaks in the older ACS 3.x Classic environment, too, ugh, I've been slowly looking into this as I have time).