I know about the XviD/DivX/etc issues, it's the Avi output code that doen't work with all codecs.
And your PC seems really slow, what model is it? The problem is that even when writing Avi files the movie is played in realtime, i.e. it doesn't wait for one frame to be written into the Avi first before decoding the next one, that's probably also the reason for the "combined" frames. I'll have a look at the source code again, maybe I can change it so it works regardless of the PC/decoding speed.