I don't know what the
real problem is... I'm pretty sure VS12 has an MP3 codec, so I think Video Studio is "confused", and I don't believe that error message... Note that the more compressed formats (like DivX) are not really designed to be edited or converted, and they tend to cause lots of trouble. (Some DivX files will work, and others will cause trouble.)
If you're stuck with DivX files, the best way to handle this is probably to find a special-purpose DivX editor, or find a video editor that just works better with DivX files. But, I'll suggest a couple of possible work-arounds using
SUPER, which is a FREE audio/video conversion program.
Can you make a file with no audio, or is it refusing to continue? Have you tried saving the (edited) file in a different format? Or perhaps as a DivX file with a different audio format? I don't know if this is an encoding problem or a decoding problem.... Usually it's a decoding problem.
----------------------------
If you can save a video-only file, load the DivX file into Video Studio and save it (unedited) in DV/AVI format. (I am assuming this file will be silent.)
Load the DivX file into SUPER, and create a (audio-only) WAV file (16-bit, 48kHz).
Start a new Video Studio project. Load the DV/AVI file and the WAV file into the timeline, and re-save the DV/AVI file with the audio and video.
Use that DV/AVI file as the new master audio/video file for your project. (After editing, you can save in DivX if you wish.)
----------------------------------------
An alternative is to use SUPER to convert the DivX file to MPEG-2 (with MPEG-2 audio or AC3 audio).
Then, you can edit that MPEG-2 file with Video Studio, and again save it as DivX, or whatever fromat you wish.