I have no idea who you are, so I only had your words to gauge or even attempt to understand the nature of your remark, and your words are obviously angry ("Get off your butt Tim!!"), short on detail, and appended to the end of a long-dormant thread. Not what I would consider "a serious question and a genuine concern", but I apologize for appearing as some random Internet troll to you.
To answer your question, I'm a user like yourself, trying to understand your problem so I might be able to help. Further, I have access to the developer forums to which I can escalate serious issues (if I can reproduce!). The dev forums occasionally get more attention than the Wild West of the discussion boards.
So, my questions were an attempt to diagnose and reproduce the problem. Let me walk you through my thought process:
- Does my account work? If not, perhaps there's a system wide failure (although two data points aren't enough to prove it).
- My account works, so perhaps your account has been invalidated for some reason. I've heard tell that iTunes U and the App Store use the same account database, so installing a free app checks your account.
- It's not uncommon for apps to poorly handle "out of space" errors, so a check of free space is a reasonable next question.
- Maybe there's a problem with the specific course you are trying to join. If you share a link to it, I will join it and see if the cource is frakked.
- Finally, knowing what version of iOS and the app your are using would help me determine if my tests matter at all: if we don't have the same versions, all of my successes are false positives because I don't match your environment.
Hopefully that helps you understand why I asked what I did. If you can provide clear steps of how I can try to get into the same situation you are in, maybe I can offer more than general advice.