I have some WMA type songs, and some of them play fine, but for some reason those WMA I download from Zune (I do have burn rights and synch rights permanently) they wont play on my phone. When I play the song, it just skips to the next one. It doesn't give me any error of any kind, it just skips to the next one for some reason.
The song file has DRM, but like I said before, I have synch and copy rights.
Any music files with DRM restrictions won't play on the Instinct. The reason is that the music player software has to be able to verify the rights. Since the Instinct music player does not have the correct software to handle this, it can't play those songs. Don't buy DRM music. It is more hassle than it's worth. I recommend Amazon's MP3 download service. You get non-DRM high quality (256k) MP3 files that you can use on practically any device including the Instinct.
That's an acceptable solution for DRM music you already own. However, it adds another generation of compression which makes the music sound worse. In the future, just avoid DRM music and either buy DRM free MP3 files or buy CDs and rip them.