Problems with Windows Movie Maker

[cpd2005]

On my WinXP laptop, I use Windows Movie Maker to create videos for YouTube. Recently however, whenever I try to add titles or credits on a video clip, its unable to show a preview as the files required to make the preview somehow had their permissions changed. The error I got was "A Required Component, Sample1.jpg, was not found." When I tried to access the "Shared" folder in C:/Program Files/Movie Maker, I received an "Access is denied" message.

So I use a Linux LiveCD (Knoppix) with NTFS read write support to attempt to view the folder that way, and I was able to access the folder and read the files. I then tried to create a new "Shared" folder by renaming the old one, and transferring the contents of the old "Shared" folder into the new one. I rebooted, and Im now able to go into the Shared folder, but the files themselves (Sample1.jpg, Sample2.jpg, so on) are unreadable.

Is there any way to make the files readable, and to change the permissions of the files? I have no idea how they got changed in the first place.