RPC: Program not registered

* when i used commander in rhel6 # howmount -e i got above error.. this error shows that "NFS Portmap: RPC: Program not registered"

So i went to hosts.allow on the FC4 and entered my address

# vim /etc/hosts.allow
i.e.
portmap : xxx.xxx.xxx.xxx/255.255.255.0 : allow
portmap : ALL

wq!

After That restart the services

#/etc/init.d/nfs restart
#/etc/init.d/portreserv restart

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