the ULP needs some temporary files that should be created in the mentioned folder. I think that you do not have the permission to write files in this folder. Basically it can be quite tricky with Windows7 to get write permission in the program folders.
What you could try:
* If you start EAGLE with a Desktop icon you can change the properties there. Start EAGLE in, for example Windows XP SP3 compatibility mode, then you should have sufficient permissions to access the program folders (as it was with Windows XP).
* Or try it with "Start as Adminstrator" (that's an option in the EAGLE start icon, as mentioned above)
* You could also change the paths for ULP, SCRs Lbrs to a location where you have full rights.
* Or you install EAGLE not into the default program folder, but into any other folder where you will have full access (for example c:\eagle)...
Hope this helps.