You ought to be gettinga lot of error reports from Microsoft about AH film viewer errors from me!
Intel 875PZ, 2.6 G P4, Radeon 9800 SE, CMI 8738 sound card, XP, 1 G RAM
It usually fails on AVI conversion or playing the same film the second time.
If I turn off the optimiztions off before I film, the problem does not arise.