Program Files NTFS Settings

Using Windows XP Professional, Service Pack 3 as well as Windows Server 2003
R2 Standard Edition, Service Pack 2.

We are having problems with permissions resetting on a program folder within
Program Files. Our vendor is swearing up and down that they don't run any
scripts that would cause permissions to reset, but at least once a day the
permissions on this folder reset so that the "Allow Modify" box becomes
unchecked for the Users group. This happens on both our XP and Server 2003
machines.

I have been searching and cannot find any information out there that says
the Program Files folder resets its permissions at any time or because of any
specific action.

Does anyone out there have any suggestions for stopping this from happening
or figuring out what exactly is causing the permissions reset? If I could at
least figure out if there's a process changing the permissions it would
greatly assist me in fixing the problem.

Thanks in advance for any help!