request not accepted

I have an in office network of about 15 computers. All of
the computers except 2 are windows 2000 professional. The
remaining 2 are windows 98 machines. This morning, one of
the 98 machines began to have errors with the network,
specifically connecting to one machine. It gives me an
error when trying to browse to the computer of "Request
Not Accepted By the Network". This particular 98 machine
can still access and browse all of the other windows 2000
machines fine. The other windows 98 machine is not having
this problem.

I can go to the specific 2000 machine and I can browse
back to the offending 98 machine. I can ping both machines
from the other. Network log in names and passwords on both
machines are correct and match. File permission settings
are valid.

I am running out of ideas of settings to check on this one.