not tried super but I have tried that (or similar) on other converters (decent ones). Also tried keeping the DIVX but converting the audio to mp3 (it seems Martin uses that format) and a few alternatives but no sound on the converted file. Not come across this before.
The original file plays fine on VLC.
Media tab gives AVC H264 as the video codec and AC3 as the audio (codec ID 2000) 2 channel stereo.
Nero is supposed to work with AC3 audio

Plays in WMP and VLC but not in Nero. Copied as Data to CD/DVD and flash stick, my 3 DVD players (plays DIVX files) and my TV (plays avi files fine) can't do anything with them. Wii couldn't see the DVD file at all.
Managed to find the Super download link so I'm giving it a go overnight

I'll let you know what happens..................
Edit.
I used super with the settings suggested - still no sound on the converted file!
Trying using mp3 audio now and Xvid. The file plays fine in Super but the converted file had no sound. No combination seems to keep the sound so I'm giving up on this one!
As a warning, the latest version of Super is packed with stuff you don't want (toolbars and the like) which you cannot opt out of installing even if you uncheck the boxes. It's going to take a while to get rid of these off my PC as they have totally hijacked stuff in Firefox - strange search bars, new tabs opening links to ad sites etc. I've uninstalled it now.