You don't get EXP for registration and can't type in your username?
To unlock further quests and get bananas the registration must pass smoothly – you must begin with a click on the "play" button on www.bananatic.com which redirects to the game website, register there and confirm email received from the publisher (sometimes it is required to download the game and log into it to unlock the quests).
You need to use a clean browser in order to avoid problems. This means you need to clear cookies, cache and your browser history.
Also remember to uninstall Adblock and similar plugins as they might cause trouble.
For further questions contact me via private message.
If you do this you shouldn't have problems earning your bananas. So have fun!