files that can not be scanned happens to all AV all the time, there will always be some files that can not be scanned for whatever reasons
but not all AV show it in the log, som need to activate advanced logging or it is hidden away in the log somwhere
i dont see it as a problem....it is just a scan error report, but yes avast could change the way the log is displayed, feks have to tabs, one for detections and one for scan errors