Starting NFS Daemon failed

When we trying to restart NFS service on Red Hat Enterprise Linux Server release 5.3 but its showing

Shutting down NFS mountd: [FAILED]
Shutting down NFS daemon: [ OK ]
Shutting down NFS quotas: [ OK ]
Shutting down NFS services: [ OK ]
Starting NFS services: [ OK ]
Starting NFS quotas: [ OK ]
Starting NFS daemon: [FAILED]

We already try by restarting portmap service but still problem is there.

So please suggest any recommendation for this issue.