[CentOS] NFS issue

Hi List, 

I must be going mad or something, but got a really odd problem with NFS
mount and a DVD rom.

Here is the situation, 
/dev/md7               58G   18G   37G  33% /data

which is shared out by NFS, (/etc/exportfs)

This has been working since I installed the OS, Centos 4.4

I have a DVD on that is device /dev/scd0, which I can mount anywhere I
like, no problem.

However, the problem comes when I try to mount it
under /data/shared/Photos/Archive1.

It mounts ok, and I can see the data on it form the server, but I cannot
see this data over the network on any NFS client when
mounting /data/shared.

If I mount /devscd0 as /mnt and export that, I can mount the over the
network fine.

If I take another device, /dev/md4 and mount in same place,
(/data/shared/Photos/Archive1) i cannot see those files over the network
either.


I do this kind of thing not quite everyday on Solaris and it just
works..

I know I must be missing something, but i'll be b*gger** if I know what.

No messages in any /var/log/* file.



Any ideas would be most appreciated?

Cheers 
AM