Doru, Thank you for your response.

>If you have SET REPROCESS TO 0 (default) FLOCK() won't return .F., it will try to lock indefinitely. I don't know why it generates GPF...

Do you mean that you don't know why it generates GPF in my case or in some other case ?

I have SET REPROCESS TO 1. I am using a Win2K machine.

Alex