Problem with Virtual Dub

Ok heres my problem i have a Archos Gmini 400 (an mp3 player with video) and i have to convert a file that’s wmv into an avi .. To convert it .. Gmini needs 2 programs .. The Archos MPG4 Translator and Virtual dub but i cant start the convert :s does anyone knows what i have to do ? do i have to download a good codec for it ?