I am not sure what you mean by "Everything".
Sorry I confused your post with another where the OP said he had "everything updated".
Does refreshing the page work ?
I did some Googling and this error seems quite rare, which is a bad thing.
However, I'd be inclined to blame Norton just because the invisible man on my left shoulder (who is always with me when contemplating other people's computer problems) is telling me to blame Norton.
He's frequently right; it's so spooky . . .
You might try Selective Start-up and see if the error stops happening when "X" isn't running.
Other than that, the only ideas I have is that this sounds more like a networking problem than an XP problem, and you might get better help in the Networking sub-forum. PM johnwill, he knows everything.