how-to for false-positive w no logs

Avast Free Antivirus / Premium Security
1

Hello,
Not sure this is the correct forum location but it seems a generic issue - not actually a virus.

  1. for the last month, I have received about 3 (out of 1000s) messages with this in the body:
    “avast!: Message body was removed because it contained a virus.”

  2. when I examine my avast! there are no log events of any sort corresponding with a deleted email.

  3. when I turn off Real-time Mail shield and ask for a resend, the message is all text!
    … though one message did have a picture attached (zdl extension after the text)

How can I prevent avast! from stopping these emails?
How can I easily determine what any such offending emails actually contain?
Where are these actions logged?

ADD:

  • am using XP sp3
  • with avast! free updated
  • also have ZoneAlarm firewall and SpyBot SD anti-malware running
  • browser default is Chrome, plus Firefox as secondary
  • email is via Eudora and generally only text-based

Please help. Regards,
James