Trouble with Movie Maker

I have been using Movie Maker in conjunction with FRAPS to create videos to post on Youtube. Previously, up until around a month ago, I simply recorded the video with FRAPS, imported the file into Movie Maker, and edited the video very easily. However, I started up Movie Maker today to begin messing around with some videos, and now when I try to bring up a video from FRAPS into Movie Maker, it just shows up as a gray box with a yellow tri-angle in the middle. When I double click the box, a pop up box appears and asks "Do you want to remove " " from the project? The file might be corrupted or in a format that Movie Maker doesn't recognize. This movie can't be saved or published until " " is removed from the project. Error: 0x87260103." This happens on any video recorded with FRAPS that I try to put into Movie Maker. Any suggestions as to how to fix this issue? The operating system is Windows 7 64-bit.