i am running an NFS Server in my RHEL 3 ws box.when i try to perform a network based installation using NFS. i have got some errors/crashs as "install excited abnormally , sending termination signals".what i will do?

one more thing,what the purpose of these files in NFS server

/var/lib/nfs/etab
/var/lib/nfs/rmtab
/var/lib/nfs/xtab