>Sometimes, I have an INSERT INTO which generates "file is in used by another user" which result in a fail.
>
>I have SET REPROCESS TO 2 SECONDS.
>
>Does this mean that during that 2 seconds, the INSERT INTO was unable to lock the header?
>
>Should I be better to move this to SET REPROCESS TO 5 SECONDS?

Yes, it tries to lock the header for 2 seconds. You can try to reprocess to 5 seconds. You don't have much to lose but wait...