Based on what I'm reading in the thread, it looks like I may be having the same issue, but I want to make sure.
When I click the opt-in link in the first post, it just takes me to my settings page where it says "Your account has been enabled for monetization" along with a message stating that to become a YouTube Partner you must comply with the terms of service. However, I don't see any new options allowing me to actually opt-in to the program.
Am I doing something wrong or was this automatic. How would I know what to check to verify if I'm already partnered or not? I have monetized videos already and have not received any new emails from YouTube stating a change.