I have a an xvid file that i wanted to demux into seperate video and audio, the audio is ac3 at the moment and if possible i'd like to keep it at that way. When i load it i get this message from virtualdubmod

Couldn't locate decompressor for format xvid, virtualdub requires video for windows vfw compatible codec to decompress video. Directshow codecs such as those used by windows media player are not suitable. Only direct stream copy is available for this copy.

Bit confused by this as i have the xvid codec installed and i thought it worked with vdm - i'm sure i've seen packs to download described as vdm+xvid. Can you get different versions of xvid, a directshow one and a vfw one ?

Which build are you using? Koepi's latest is 1.1 which works good for me. VDM _SHOULD_ work, although i have seen that error before for not having xvid installed. Are you sure you have xvid installed? Please update to the newest build of xvid as the previous version sometimes made VD/VDM not detect it. Also, i would recommend using Nandub for demuxing audio/video as it handles more audio files, such as VBR MP3.