Do you have any sort of backups? You may have destroyed them.
Things to try:
Log into the Mac with a different user account.
Try to open the files checking the "As a copy" box in the dialog.
Try opening on a different computer.
Thanks Peter, I will try and see what works. So, for me to understand what's behind this problem.. what was thrown into the rubbish bin during cleaning? Back up-files, other files? And how will this effect using adobe on my computer?
I don't know a thing about AVG Cleaner, but tools like that scare me in general.