I'm not sure I can explain this clearly enough to get help, but I'm going to
try.

I have a bunch of queries, and forms based on those queries which were
working just fine.

I have several front ends which access the same back end.

Somehow, about five forms, based on different queries have stopped accepting
new entries. Different versions of the front end have the same problems.

I am fairly confident that I did not mess with the queries, so I assume that
I somehow deleted or changed a key relationship. Is it the relationships
that are given in the back end that matter, as I assume? Any wild guesses as
to what I might have done?

Thanks for any help you can give me, I realize that this is asking for a
wild stab in the dark.