Xbox 360 - I can see playlists but not songs - Please help!

I downloaded Zune and tried to stick songs into a playlist that I made. But when I access a playlist from my Xbox 360 (all of my playlists are registered...) it always says "no songs in playlist" (for all playlists) so I'm wondering what I'm doing wrong??
I even reset my computer and logged back on and the songs were there (as in, they were saved) so that's not an issue.
I can't find any place on the internet that has an answer, so please help!