An existing server did not respond to an NFS mount request, so after retrying a number of times (default 1000), the mount(1M) command has given up. Nonexistent servers or bad mount points produce different messages.
If the "RPC: Program not registered" message precedes this one, the requested mount server probably did not share (export) any filesystems, so it has no NFS daemons running. Have the superuser on the mount server share(1M) the filesystem, then run /etc/init.d/nfs.server start to begin NFS service.
If the requested mount server is down or slow to respond, check to see whether the machine needs repair or rebooting.