Windows Live Movie Maker won’t accept its own file?

So here's the thing

I have a video that I have put together into a movie. The audio is soft so I cranked up the video sound in the adjust option section. But because I did that, I can't make a proper intro/opening section with an MP3 playing over the title card because I sacrificed music volume for video volume.

Okay.

So I open a new project, make the title card with music audio, and save it as a movie. No problem.

When I try to import it into the actual video I'm making in Movie Maker, however, it shows the clip as grey, with a little hazard triangle on it, and when I double click that to "fix" it, I get this message:

So....my question is what the heck do I do now?