If its supposed to work on XP then they should have a fix for the problem. Cos this seems like a major bug to me. But then it could be a problem with XP itself, in which case it could be more difficult for Symantec to solve the problem without MS help.

But if u have a corporate agreement with Symantec for the Anti virus software then, like ichnisan said u should be upgrading to version 8. This would solve that problem and maybe help u out in a few other ways as well.