DavidR
2
The windows file error 1006 = The volume for a file has been externally altered so that the opened file is no longer valid.
Though there is an avast Knowledge base entry for this, does it ring any bells on your system ?
http://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=162&nav=0