Using PD on Domain Macs

Hey Everyone

Fingers crossed you can help/confirm the issue I am having.

Background -
In a school, Domain Connected iMacs on 10.5.8. They log in using their AD accounts and run a Windows VPC on the local hard drive. The students can open the parallels Virtual system to do their work (2D design which is not available for Macs :-( ) They then drag the files onto their network for backup.

Problem -
When opened, the virtual machine "locks" out users giving a permission/rights error.

Findings -
If I get info on the pvm it says the Owner is the previous users account. If I reset all the permissions and copy back the pvm (its in /Users/Shared/Parallels/) it works again with the domain user (with the local admin user as the owner). If the user QUITS the application by going to Parallels Desktop -> Quit the system works fine for any user after that. If they do not do the correct quit then log off this is when the error occurs. The students have Full Read and Write access to the pvm (or it wont open for them).

Solution -
The obvious solution is they quit the application correctly each time. Unfortunatley the students (and the teachers -.-) do not do this and after 1 year of this issue do not seem to understand the importance of doing this.

What I need to know is there any way of either making the cross close the actual application OR giving different permissions to the students in a certain way that they cannot take ownership.

I must admit my Mac knowledge is minimal, I have no Mac training but I am currently in charge of 100 Macs and a Mac server! Any help you can give would be greatly appreciated.