Do not extract the zip file, just save it to your Add-Ons folder.
If you are using Windows Vista, move Blockland out of Program Files if you have it there. Vista handles it very strangely and it can cause errors.
You cannot use RTB if you have the demo version of Blockland.
If you're sure you've fixed those things, run the game, close it and post the console.log file you should find in your Blockland folder here.
