@Asyn - Thank you for the reply. Unfortunately there is nothing at the supplied link that will help me with this issue. Does any one else have specifics as to what is causing this problem, and how to resolve it?
EC 00000005 means ERROR_ACCESS_DENIED . Did you set directory C:\Windows\TEMP_avast_\unp143831085.tmp as output path for AvastPE.iso ? You probably don’t have rights as standard user to write there.
@Martin Kudlicka - Thank you for the reply. No, the output destination for the iso was a newly created and empty folder on the desktop. The temp file path shown in the event log was created by Avast, in the process of attempting to create the iso.
@Martin Kudlicka - This issue has been resolved. Your explanation of the error code prompted me to look at Windows/Temp. I had a permissions problem, and was being denied access. This has been rectified and Rescue USB/Disks are now reliably created.