NFS & rpc.mountd couldn't rename /var/lib/nfs/rmtab.tmp to /var/lib/nfs/rmtab

[Hanasaki JiJi <hanasaki@hanaden.com>]

What causes the below and how can it be fixed?  what is the impact of 
the below?

debian version = sarge

Thanks,

rpc.mountd: couldn't rename /var/lib/nfs/rmtab.tmp to /var/lib/nfs/rmtab