w/D7, w2k/SP4, IBO 4.2Hd

I have an IBODatabase, and some IBOQuerys.

With one of the IBOQuery components which only occasionally makes an
insert, an attempt to insert a second record in the program's cycle
results in the error

Violation of Primary or Unique Key constraint "INTEG_8

The PKs are generated in a trigger.

If I insert a new record with this IBOQuery component and then
shut the program down, and restart and insert the next record,
there is no error.

My only guess is that this has something to do with the commit process.
I have tried calling IBODatabase.Commit after the insert, but this
makes no difference.