I am not sure where to ask this question.

A user (my boss) can access the SYS volume of another server in a different
Tree but cannot access the other two volumes, which are LONGVOL and VOL1.
He has the same rights as I do. ADMIN all the way.
I can access everything. I have drive mappings to everything, but he can't,
at least on this particular server.
He can access all volumes on another server in that same Tree.

When he tries to access LONGVOL, a message appears:
\\vbl2\longvol\ refers to a location that is unavailable. It could be on a
hard drive on this computer or on a network. Check to make sure this disk is
properly inserted, or you are connected to the Internet or your network,
then try again. If it still can not be located, the information might have
been moved to a different location.

We are using client 4.90 sp2.
Servers are NW6.0 SP5 (in other Tree). Workstations XP Pro.
IP only.
Any ideas would be helpful.