[Samba] Permissions problem

[Madison Kelly]

Hi everyone (oh yeah, and I am new to the list but have a little Samba 
experience).

I have a Samba 3.0.1 install on a Fedora Core 1 (.2138 kernel non-smp - 
not that it should matter for this). I have created a group called 
"osla" for the users in my domain and I have Samba working properly as a 
PDC, or at least properly in so far as I can join clients to the server, 
run scripts and so forth. I am using the simple 'smbpasswd' backend and 
have made sure that users are members of the "osla" group and that their 
passwords are the same as the Linux 'passwd' passwords. Finally, I 
chown'ed all the files and folders in the 'public' share to 'root:osla' 
and then chmod'ed all of the same files to '775'.

My problem is that when the user runs a program from their workstation 
that needs to write to the public share it fails saying that it has 
insufficient permissions (ie: Quickbooks; app is on the client PC but 
the data file is on the Samba share). If I then chmod the effected file 
to '777' and the program suddenly works. Oh, the workstations are all 
Wind2k Pro SP4 machines.

The best I can guess is that despite the user being logged in and a 
member of "osla" the program must be running under another credential. 
Am I right here? Users manually can create, delete and edit folders and 
files and apps like MS Office can open and edit files.

Can anyone point me to what may be wrong and perhaps suggest a better 
way to resolve the problem without chmod'ing directories and files 777?

Many thanks!!

Madison