I want to post my own song I just created. There is no option anymore? Did it move. I can post remixes, samples, etc. But not an actual song. Hmm? What am I doing wrong?

You are correct. Full mixes are no long an upload option. This is how ccMixter is different than Soundcloud, Jamendo, and all of the other places where you can upload full mixes. However, you can upload all of the stems in your mix (I put them in a zip folder or two) and upload the full mix as a preview.