hello Helen,

thank you for your exaustive reply. I will check for any circularity.
Maybe it could be that when the after delete trigger for table 2
fires, it still expects to find the rows it has to update in tables 3,
4 and 5, but in the meanwhile the cascade process could have already
deleted those rows.

I have built those complex triggers that fire after insert, update and
delete because I wanted those tables (that contain totals) to be
automatically maintained, even without using the real application (for
example using some tool like IBConsole, IBExpert or so). But if I
still encounter problems like this, I was thinking to move the trigger
code into stored procedures to be explicitly called into the
application after any insert, update or delete to maintain total
tables. Do you think this could be a better solution or is it better
to resolve the circularity problem and leave the triggers as they are?
Using SP's the database is no more auto-maintained (for totals).

Cheers
Salvatore