Hello PCLEUSB2,
Yes, those are the files you want to delete (except your main video file). After you have deleted the scn and index files or any other files you may have after your main video file, open studio 12.1, open the avi file video you want corrected, double click on the video thumbnail of that file and let studio re-detect it again. You should be able to use it without any problems.
NOTE: Once you have this file with studio 12.1 and want to return back to studio 12.0, you will have to do this step again in order for it to work again. I don't know why but thats the way I found out after having too many problems with studio 12.1 and had to return back to 12.0. Good Luck
I already made a quick test on your file you had problems with and everything worked great for me (with studio 12.0) but had to re-make it into an AVI file again and store it in my AVI personal file I have. Should work too with Studio 12.1 (if not try an earlier version of studio and make it into an AVI File and use Studio 12.1 to detect video scenes)