Multiple Attempts before Eraser Finally works



I have been most happy with both versoins 5.3 and 5.7 until recently.Lately I have been getting a message that the file is being used by another application.I know this is not apparent, at least to me.I have to attempt to earse 6-7 times before it actually works.It is really annoying because the process was so convenient previously.I have ran Scan disk to no avail.Have deleted everything and loaded a new version to no avail.Closed everything else before using each time.
I am running Windows XP.Can I be sure that Eraser is actually working? Can you advise please as to how to fix this ?
Which file does it list when giving this message "the file is being used by another application"?