Use of music in an animation...

[jgannon]

Rules are rules. You can't do something beyond the bounds of fair use just because it would be really really cool. (My views of fair use vary a great deal from those of the government, but that's not the point.) If the work is public domain, then it shouldn't be a problem. IANAL, but if the work is copyrighted, then my understanding is that FIRST requires written permission from the copyright holder for you to use the music in your production. If you are unable to get permission, then you can't use it. I'm sure you're really excited about this music, so I hope you'll get the permission you need, but if you can't, bummer.