This now occurs for me using the latest MP, 0.2.3.0. They are MP4s and used to play fine. They still play fine using Nero Showtime but no longer in MP.
I have the same problem with the latest version of mp per 01.12.07 (have'nt actually tried any older versions.) I have tested the solutions here, with no luck. I also restored the computer, but the problem persist. may this have something to do with the vga-card driver?
did anyone find a solution?
I will try to uninstall and install rc3