Win XP SP1 Crashing when transfering files

[DoG]

Anyone else come across this problem before? I can browse each machine with the other, have internet sharing setup through the WinXP machine with out a problem.
As soon as i try to transfer files from the XP machine to the 98 machine the XP machine restarts its self.
Going to turn BSOD's back on but can't risk a file transfer again as the XP machine contains my mail server etc.

Thanks for any input