So I'm trying to move some files I've shortened (music files) to my HTC 8x Windows phone's Ringtone folder through the usb mass storage folders. I drag it and drop it, and it says copying, but it takes a minute or two then says there's a problem with copying it. I've tried to check for DRM and even converted it from mp3 to AAC. It still seems to have the same problem.

Is there something I'm not doing correctly to get this file over to make it a ringtone? I mean, it's only 10 seconds long and definitely under 1mb. Am I missing a step somewhere?