avast! Showing corrupt archive files.

Hello!

I have recently done a clean install of mountain lion onto my iMac. After about a week of using it, I decided to run an avast scan on it, after realising that I have disabled the web shield instead of the mail shield. The scanner is currently running, and so far has picked up several corrupt files - some in /developer some in "/developer (from old Mac)" and some in /.documentrevisions. I'm not really sure what this means, but is it anything to worry about, or are corrupt files following a clean install quite a common thing.

Many thanks!