mount problems

[Christine Gregory]

One of our rs6000's is giving us (more than the ususal amount of) trouble:

When trying to mount an nfs filesystem, it gives

clnttcp_create:  RPC:  Port mapper failure - RPC:  Timed out
rpc.statd:  cannot talk to statd at ibmb0

What I don't understand is that there are 4 other *identical* machines
(all 5 are 320's) that were set up *identically* to this one (except for
the hostnames, etc., of course); and they work just fine.
Also, this troublesome 320 mounts NFS files from another 530 (ibmb0 is also a
530) just fine.

Anybody seen anything like this??

RTFMing (or is that RingTFM?) was no help.

Thanks.