Permissions problem under nfs

Hiya

I have a few rogue directories on our NAS that I can't seem to change as root, we've migrated from using infrant NAS units and the user/nfs options are a bit different, so I may have mis-understood something and to be honest, my permissions knowledge falls down a bit on nfs with shared smb clients etc;

On a client linux machine, logged in as root I do;

$ls -l /mnt/nas12/blah blah blah - this gives;

drwxr-xr-x 3 apache apache 16 Jan 9 15:45 foldername

when I do
chmod 777 /mnt/nas12/blah blah blah I get

chmod: changing permissions of ... : Operation not permitted

The configuration is that 2 linux units and half a dozen windows ones share the nas. The folder creation is all scripted and automated - so no real users on any system. I get the same error from either linux unit.

The open-e nas is configured as follows;
MODEL NAS-R3, Version 4.32DB00000000.2862

SMB - Visible / Guest (anyone without password)
NFS - All Squash / No root squash plus appropriate allow and write IP's

I'm sure this is dead easy - what I don't understand is that I can create and change permissions on other folders fine - but it seems that root access isn't being granted to the root user?

:confused:

Grateful for any assistance

Roger
London