well, if the system doesn't have enough ram, then it will cache to physical disk. If the disk is running on low disk space then that could cause this error. Also, if your using cs3 at home, are you sure your doing it in a v6 compatible format?
Yes it was a .psd which should and normally open in any Photoshop version.
Not only that, but who takes care of the maintenance on the college computers? Such as, cleaning out old Restore Points, if any, using Disk Cleanup/Defragmenting programs of the HDs, removing old, unused programs, running malware apps, etc., etc.. You may be on a college PC that just needs a "tune up".
Yeah I must admit, I didn't have time to try another computer, I have never had problems before.