Just for troubleshooting purposes--if you flip the order of the two videos, does the order of the problem also flip--or does the trouble then happen to the first (i.e., when it's played second). If it happens in the second position regardless of which clip it is try placing a simple instruction item between the two clips and see if having a delay between them helps the second one play. FYI, I noticed that if you zoom in on the image, it looks a lot like bits of colour and shapes from the old windows media player (which you can see from typing mplayer2.exe from the Run command on the Windows Start menu.