NT Workstation won’t Telnet

I have a NT 4.0 SP6a w/s that is setup on an
NT Domain. The network strictly uses TCPIP. We can get to the domain and all shared resources just fine. We can not Telnet to a
RISC 6000 Unix box that runs our Production App. I can PING the Unix Box, I can do a TRACERT to the Unix Box but when I try to Telnet to it I get an error saying Network not available. It appears to be a problem with this particular workstation as I can Telent from other workstations but I cannot Telent from this one to the Unix box or to the router at this remote site. Any hekp would be appreciated.

Thanks
RJ