I've not really played with this sort of stuff yet, but I'm guessing that tsMuxer is just a muxing utility - the clue is in the name! :)
So if your ts files are in MPEG-2, you will need to reencode to H.264/AVC format (x264 should be suitable).
Even if the ts files are already in H.264 like Howard the Duck, you will probably still need to reencode to fit on a DVD9.