Using group policy preferences to push a file to C:\Windows on a restricted user
Solution 1:
Make sure you haven't checked the "Run in user security context" box on the files you're pushing out. That would be on the "common" tab in GPP. If that is unchecked and you're still getting the error, it would be a very good idea to try and get this pushed out through the Computer GPP. Since these are probably student machines, they're likely in an OU that's full of them anyway.