Rovy, when you say choppy, do you mean that frames seem to be dropped "out of the video" or does the video look basically like a speed-up slide show of pictures and not a animation?
If its the latter, you might just need to increase the fps before exporting the .avi in monkeyjam.
If its the first problem, it gets a little more complicated. I have this problem when I try to play any large video files on basically any Microsoft program (i.e. Media Player, Movie Maker, etc.)... it always seems to lag. Compression would help with this problem as there would be less video file to "buffer" but I wouldn't recommend compressing the video file until you have the final production to save as much picture quality as possible.
I guess my real question is, why would you even need to import the video into WMM? It's my understanding that Lightworks has the same functionality as WMM, only its much better.
If I'm on the forums, I'm probably waiting for Blender to finish rendering.