Server not accessable

I have a stand alone server in my domain that I am trying to install Symantec
Anti-Virus for Servers. I have sucessfully installed this prodcut on all of
my other servers (both stand alone and AD/PDC). This one will not install.
The setup program complains that the "server cannot be found".

All other access to this server works (i.e. from any WS or Server, this
Server can be found and browsed via Entire Network)

Any ideas what might be wrong?

TIA,
Ed.