3. Remove your Twitter browser cookies and hit F5 (or CTRL + F5). Yes this works. I spend a lot of time on Twitter, heck i even have a blog about Twitter. I use lots of API calls. And the over capacity can be just for you, not Twitter yet shows the same error page. If it shows "You can't do this action. Come back later". Or somewhat along these lines do number 3.
Note: You will be asked to enter your password.