Clip won't play in Sony Vegas Movie Studio 9.0!

[xPiikanyaa]

Okay, so I had a video on my computer that I need to put in my AMV, but it won't play! The audio keeps skipping, the video keeps freezing and parts of the screen are green. Like this: http://img514.imageshack.us/img514/1993/26073002.png
The video is a .mp4 file type (and yes, it IS the opening to Azumanga Daioh =]) and it works fine when you watch it in QuickTime, just not in Vegas.
Does anybody know why this happens and/or how to fix it, if there IS a way to fix it?

[AFT]

I won't even ask why you're editing with mp4 files. Vegas usually has problems with mp4, especially when it uses DivX, Xvid, and h.264 codecs... Usually Vegas won't even take it, and tell you it's of an unsupported file type. But when it does, those errors are likely to happen.
If you absolutely must use that mp4 file, use ffmpegsource to import the video in avisynth, save it, then open it in Virtualdub, save it as an avi and use that file for editing. It shouldn't give you anymore trouble.

[xPiikanyaa]

I won't even ask why you're editing with mp4 files.

I had it in mp4 format because I originally had the videos on my PC to watch on my iPod, before I got into making amv's. That's why. Thanks for your help!

[xPiikanyaa]

I changed it to an .avi file type but when I drop it in the timeline, only the audio track appears, not the video track. I heard this is because the of the codec, but which codec is best for editing in Vegas???

[Kariudo]

lagarith

it's lossless, so be prepared for hueg liek xbox files