Sorry but reporting just the malware name from the boot-time scan doesn’t help, what helps is the file name and location of that file.

Look in the C:\Documents and Settings\All Users\Application Data\Alwil Software\Avast5\report\aswBoot.txt file (XP location) Or C:\ProgramData\Alwil Software\Avast5\report\aswBoot.txt (Vista, Win7 location), check this file using notepad for info on the scan/detections, etc.