Corrupt files indicated may only mean that avast can't extract the files in an archive file, so it guesses at corruption. Can you give some examples of the file names (including file type, e.g. .rar, etc.) of the files that are corrupt ?
Again there is little to worry about if the file is corrupt there is little you can do other than try and find a replacement. But if your system is running find and you don't get error messages when running your applications that a file is missing or corrupt, you have little to worry about.