I succesfully added subs to an AVI earlier tonight to one video file. I took the AVI file, then took the SRT file and named them both the exact same thing. I then clicked and draged both files into VobSub, clicked on Mux, and in a few minutes I had my finished AVI with the subtitles succesfully added onto the video.

I am now trying to do the exact same thing for another video file and subs. However, when I click on Mux for this one, and then save the file, it just works for a split second. The file that it creates is a tiny file size, and isn't a video of any sort. When I try to play it it shows a time of like, five minutes, and no sound or video is available.

Why would it work with the first one, but not this one?