This automounter message indicates that the system tried to mount a filesystem from an NFS server that is either down or extremely slow to respond. In some cases this message indicates that the network link to the NFS server is broken, although that condition produces other error messages as well.
If you are the system administrator responsible for the non-responding NFS server, check to see whether the machine needs repair or rebooting. Encourage your user community to report such problems quickly but only once. When the NFS server is back in operation, the automounter will be able to access the requested filesystem.
For more information on NFS failures, see the section on NFS troubleshooting in the NFS Administration Guide. If you are using the AnswerBook, a good search string is "NFS Service."