Unable to Access Wireless Hard Drive (LinkStation) Files

I have been using a Buffalo LinkStation Pro LS-250GL High Speed NAS Wireless
External Hard Drive and all of a sudden I can't network with it. It has
worked fine for over a year on my primary XP (SP2) laptop, and 2 other
laptops I own (both XP SP2) have no problem accessing the hard drive and its
files.

Now - although I can access the hardware through its web interface and can
log in and change settings, it won't let me access files.

I have been in contact with BuffaloTech support as well as Symantec/Norton
and both insist that something changed in Windows to cause access problems. I
have disabled and re-enabled Norton Antivirus and uninstalled and
re-installed the Buffalo LinkStation software and updated their firmware to
no avail.

I haven't used the external drive for a month, maybe 2 months, and I doubt I
could rollback far enough to a system restore point to see if that would
solve the issue.

Is there any other way to see what could be causing this issue?