I have looked at the video tape several times and it does indeed appear that Romo is winding up right when RW is chucked, so it is possible and quite probable that this illegal action caused the pass to appear to be inaccurate.
When I saw this play happen on replay, I thought to myself were the refs picking their nose and looking at their buggers because it was so blatantly obvious and I've seen Cowboys players get called for the same thing?
But, then I realized it's the refs in the NFL (who are consistently horrendous) and they obviously are told to call the games a certain way when the Cowboys play, and that is almost always against them in the sense of allowing other teams to get away with more "physical" play, especially if they are on the road.