Ok, I did some research about this error. I actually downloaded a video uploaded by some user and tested it on my own comp (he reinstalled his windows to fix the error O_o). The video had corrupted keyframe information. All above users are correct to use AVISynth to rebuild the keyframe information, but if you are being unsuccessful then I can give an advice that a times helps me. It is the reason why I asked you to tell me, if the video was showing any pixelation or corruption in media players.
Use TmpGenc or TmpGenc Xpress HD (i use it and i love this tool), and reencode the video using directshow as your encoding source, and you'll eventually get your video in a new format. Probably HuffYUV rocks!! ^^.
You know why would directshow work...right?
