Can you provide a site link and/or the markup you are using?
When posting your markup here on the forum follow these simple steps:
0. Login and paste your markup into the Message Box.
1. Mouse select the markup you just pasted.
2. Press the More Button from the Message Box Toolbar.
3. Select Raw text from the drop down menu. DONE!
If I don't respond to your POST, it's your inability to provide your markup correctly.
Check out a few DEMOS I made that are here in this forum.
Mine is doing the exact same thing in IE. The first time I view the .mp4 movies (everything play fine).
When I close the movie, and then go to open it up again... (boom, shows half white screen just like above).
If I am going to shell out money for a license I would at least like to know that this is something that is fixable.