Here's how to check that it's definitely a bug in the Open Ads Plugin:
Check:
http://www.venetubo.com/images/flash/v3/flowplayer/example/test.html
it should work...
now try this one:
http://www.venetubo.com/images/flash/v3/flowplayer/example/tracker.html
it will fail.
The ONLY difference being:
In the 'test' example, I use the 'shows' property (which is like the equivalent of playlists) for video streams in the Video Ads Plugin.
In the 'tracker' example, I use FlowPlayer's playlist property.
so, its pretty obvious there is an error in the way the 'Video Ad Streamer' handles playlists. I already reported the bug, and provided test cases for the developer including some detailed information.
Edit: In some cases, if the second example works, it is because NO pre-roll was scheduled to be run. (OpenX is kinda funny, because it seems to have a mind of its own when delivering remant)