Problem with certian mpeg files

[wms3]

MF 2 or 3 will not open certain mpeg files created by my Hauppauge TV tuner cards and Sage TV. The mpeg2 files will play fine in windows media player and Win DVD. The files have mpeg audio and are VBR, the bit rate being around 7 mbps. Now if I create a file with a lower bit rate, 6 mbps, all is well. Various players, and even windows movie maker will open the files. It seems that this is an issue with Ulead.