NSS volume Management - iManager & OES2

Just something a little wonky on a couple of recently installed OES2
servers at a client's site.

When accessing the Storage|Volumes task in iManager and pointing it to one
of these servers, we randomly get an error: Storage error

File Protocol error occurred: cannot open the NSS version file on the
selected server. The NSS software may not currently be running on this
server.


When accessing the servers directly, the NSS daemons are loaded, running,
happy little guys. I can manage the volumes through NSSMU at the servers,
and the users are able to connect and access their files. The weird thing
is: last week, I got the error for one server but am no longer getting it,
and now am getting the error for the 2nd server (which wasn't happening
before).

Any ideas?