NFS mount problem

[Howard Lowndes]

I have a vfat partition mounted on box A and I am then trying to nfs mount
that from box B.  Box A looks to accept the nfs mount request OK judging
by the /proc/fs/nfs and /var/lib/nfs entries, but box B is still denied
the access; the message from box B (NFS client) being:

 mount 192.168.255.131:/mnt/hda /mnt/disk/
mount: 192.168.255.131:/mnt/hda failed, reason given by server: Permission denied


I have /etc/exports and /etc/hosts.allow set up OK.