Thank you from me, too! 8)
I was stumped by the Delete (personal) Group problem I encountered after I installed Niels' Delete Inactive Users mod (http://mods.db9.dk/viewtopic.php?t=460
I'm unsure this is related to his mod per se. He requested that we try deleting someone using the regular ACP Members Management form. I got the same problem -- suggesting it is a problem with the underlying database.
Tommy's (dkklein) solution assigns Personal Group IDs to inactive accounts -- then allowing Niels mod to do its thing.
Whew! Blew 2 hours trying to figure this out