This what I received from WinAvi:

Dear Sir,
I'm so sorry about that.
The WinAVI Video Converter 7.0 would be released in June.
I think it would have a more effective way with the Xvid encoder.
And at present, would you please just use the Divx as the encoder when you convert the file to AVI format.
If you have any other problem, please contact with me and give me the detailing about it.
Really apologize for the inconvenience.
Yours
Sincerely