>>I have a Form with parent/child forms. Is multi users.
>>when I insert a record and many users use the form, the error is produced. and I then select an option (cancel or ignore) and the application break!
>>
>>I use bufferMode = 3
>>And begin - end transacction when insert record
>
>What is the error message? Presumably, inserting new record can produce nothing more then index uniqueness violation.

The problem is when they are many users using the System. And the worst it is that the system breaks after showing the message of error.