a quick look says it is the duplicate From:
[email protected]line.
Where is it? I don't know.
But I do recall on the very old versions that there was a email option to set it to send text,html or both as a email format.
If that holds true for your version this feature is probably the culprit and you may want to turn off one or the other and see if it will deliver. That feature no longer exists in current versions because it is not needed now.
