I'm studying the technical information shett "Maintaining an Auditable
Series" by Jason Wharton

www.ibobjects.com/docs/ti_AuditableSeries.ZIP

He wrote :
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Mix in a little conflict...

Free up some more invoice numbers by deleting some more headers.

Now, open another instance of the application by running the EXE from the
project folder.
Line up the two instances so that you can observe both the header and log
grids of both.

In one instance, start to enter a new header, but don't post it.

Do the same in the second instance but, this time, try to post it.
Observe that you get a Deadlock message.
This is not a problem - it shows that the lock applied in the Before Insert
trigger by the first instance is working.
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the problem is that i'm not able to get the error

what's i'm missing ????

i'm using : Delphi 5, IBO 4.2 Id, Interbase 5.5

Thanks in advance,
Best regards

Stefano Campri