First of all, its not a matter of the kernel but if your running the correct daemons for NFS.
Read up on the NFS howto at www.tldp.org
or view the man pages on it already on your system, man nfs
Plus make sure the system your trying to mount the shared directories are configured properly on the NFS server with the correct daemons as well. The man pages and the howto's should get you going in the right direction.