Print Sharing and Outlook Express

Ok, here's a new twist on an old problem.

I have a network between Win XP and Win 98. When I share my HP 5550 printer
(which is attached to the Win 98 machine) and I try to access it from my Win
XP machine, Outlook Express 6 on the Win 98 machine ceases to work. It says
it can't find the host.

After disabling printer sharing and rebooting, Outlook works again. During
all of this, I can still browse the web and everything on the XP machine
works fine.

Can anyone tell me what the relationship between printer sharing and Outlook
Express is?

Thanks,

....Scotty