Permissions Changing
 

I'm having a problem with Mandrake 8.1 where the permissions on directories inside /home change automatially. For example:

/home/jobs

jobs is owner=ernie, group=production, owner=rwx, group=rwx, others=r--

If I look again in about 30 min the permissions have changed to:
owner=rwx, group=r-x, other=r--

The directories in question are used as Samba shares. Everything has run okay for about 2 years and this problem cropped up when I upgraded hardware and installed Mandrake 8.1 to replace 8.0. The Samba config file has remained the same.

8.1 had lots of problems, look at 8.2 or even 9. If you don't want to do that, maybe go back to 8.
Is there a user called jobs? if so that could be messing it up. What daemons are running, anything that could mess with permissions? (linuxconf etc)