Hello.
I got strange problems with codecs (I think) on Windows 7.

I'm trying to edit MP4 video files on VirtualDub. I'm using the DShowInputDriver plugin for opening files (the MP4InputDriver plugin doesn't work, it screws up VDub and makes it crash) and it shows the video just fine, but the audio doesn't work, when I try to play it in VDub I get this error:

No audio decompressor could be found to decompress the source audio format.
(source format tag: fffe)
The very strange thing about this is that on a Pentium4 running Windows XP SP3 it works just fine! (I use K-Lite Codec Pack on both computers) I can edit MP4 videos on VDub with no problems and I didn't have to install anything extra besides the DSID plugin for it, while in my Windows 7 computer I also had to install the "cole2k media codec pack" to get Media Player Classic work fine, because without this pack MPC takes a few seconds to load a video file. Well but this isn't the problem.

So anyone knows how can I fix this? I'm still able to edit MP4 files on VDub as long as I disable audio or (what I do) extract the audio from the video with another program and I insert it through the "Audio > Audio from another file..." option.
But it'd still be nice to get VDub working with MP4 normally.