Re: Workaround
 

I really don't know what to do finally... DivX codec is added to Vegas, but no any result - divx is still non-compatible with my Vegas. I see divx.dll in FileIO Plug-Ins>aviplug directory of Vegas.
Very very very strange...... :(

Plamen, I don't know the pack you are using but till now I've seen tousands of warnings not to install codec packs!
The problem might be not even in your video codecs but in some of the audio codecs included in the pack or more likely in some of the filters.
Also often different codecs are trying to 'still' each other's priority for reading their format.
So I would uninstall the pack and all addtional codecs and then install only the one I really need (and one at a time). This way you can at least reduce the possible causes.
Good luck!

Why don't you render it to "raw" avi in VDUB and throw that in vegas , don't any reason why that should be a source of problems