Can we step back for a moment and think about this? Amazon MP3 files load correctly in virtually all music players, including ones running on the original poster's system. The ID3 format can be easily read and edited from the MP3 files.

It's certainly possible that Amazon is watermarking the files and that the watermarks are in some way interfering with a bit of random software that tries to do something clever and off-spec, and it's also possible that the original emailer set up his software wrong, but it's not likely that Amazon is doing anything magical with the tags themselves.