File Locks on NAS

Hi all,

I'm not sure if this is the appropriate place for a post of this query
- but I'll try anyway.

At my workplace I have installed 2 Buffalo Terastation Pro II
rackmount drives.

Previous to this I had a small network set up for multiple laptops to
access some databases, offline from our main servers. This was an
extremely simple setup and just used Western Digital Mybook World
drives attached to the network. One of these drives failed, and we
decided to go up a level into a RAID system.

However - prior to the failure, multiple users could access a MS
Access Database. Since moving to the Terastation, this is now no
longer possible. Only one person can access the database file, anyone
else gets no response when trying to open the MDB - no access splash
screen, nothing happens whatsoever. When the user closes the MDB,
someone else can access it again.

I've been told the Terastations run Samba, and therefore I wondered if
it might be something to do with permissions etc. When I investigate
the permissions on the MDB file, there are Permissions for Everyone,
and 2 sets of Unix Permissions. If I try to alter the unix
permissions for Full Control, and apply these settings (either with
Vista or XP Pro) they are not saved.

Is this what may be causing the file lock or is it something else?
Sorry for the rookie question, but I've never come across this issue
before and I'm clueless about Samba. Its critical I get this to work,
otherwise I've just wasted a lot of time and money on these drives!

Thanks