ERROR:Failed to use DirestShow video Engine

[drummin4him]

first of alll, what does that mean, and secondly, how do i fix it? i have made a video before and this didnt happpen.

i am in the process of creating a photo montage, and then that came up... so i pput previous vidoe footage in and the erro still popped up!! agh! please help!!! thank you so much!