WinDVD BD program won't play Blu-ray moives

[tlee23]

I have Plextor PX-B900A with the leastest firmware v 1.01. It came with the WinDVD BD Program and Ulead burn now. The burner wroks, but I can't get the WinDVD BD to play any of my blu-ray moives that I bought from the store. For the WinDVD BD I have Version 7.5 B43.195. Anyone have a clues on what the problem maybe?

Thanks