Strange. Ok, if there is any background footage in the project, remove it from each layer and try again and see if the problem persists.
If it does, zip the project file (ip3) and send it to me at support at wondertouch dot com.
You could also try turning off motion blur, or switching from HQ to regular blur, or try with not saving alpha, or some combo of those. Those are the first things I’ll try anyway with your project if I see the same results you do.
Alan.
http://www.wondertouch.com