Problems Playing Music in Amazon Music Player?

A

AC Question

So I had downloaded some music onto my phone a loooong while ago. I decided to delete it all and download some newer songs so I went into my files and deleted any file that had "music" in the title.

Then I got an app that downloads music and I downloaded a bunch of songs. But when I went into Amazon Music Player to listen, a message that said the format couldn't be supported? And that I had to fix the format?

I never EVER had this problem before. I own a Droid Motorola Razr. Help me plzzzzzz