iTunes wont play some songs but iPhone will..help?

I've added a few new songs to my iTunes library and for some reason they won't play - it just skips all the new songs. They also say "Not Available" under the "Time" column. But they're playing just fine on my iPhone 5 after syncing.

I tried compressing the files by doing "File>Create New Version" but that didn't help (I tried it with all possible file formats).

I just updated iTunes to the most recent version and that didn't help either.