Please, go to Start menu / Run... and copy&paste the following command line there:
dir "C:\Program Files\Alwil Software\Avast4\*" /s > c:\avastdir.txt
When you run it, it will create a file on your C: drive (C:\avastdir.txt) - so please attach the file here (or you can send it to Maxx's e-mail, if you wish).
Another thing worth trying - please go do avast! settings and on the "Report file" page, enable the report file generation and make sure the "Hard errors" option is checked (you might want to uncheck the other options of "Log Record For", because it would enlarge the resulting report). Then, run another scan and send us the report file (by default, in C:\Program Files\Alwil Software\Avast4\Data\Report\Simple user interface.txt).