Try downloading the default minigame add-on. Open Blockland, enable all the add-ons you want enabled at the Start A Game screen, click Launch Game. Once the server starts, close Blockland. Open your Blockland folder, run dedicated.bat.
Once the dedicated server console confirms that the server is active, reopen Blockland, join your dedicated server, start a mini-game, type /setdefaultminigame, then type /dedicateminigame. However, that is only my guess, because the two add-ons seem like they would conflict, seeing as the Default Mini-Game script makes it so people can't leave the mini-game, but the Dedicated Mini-Game script allows the owner to leave the mini-game. Hence, this method seems a bit screwy. You're better off asking for help from someone like Destiny, creator of the Dedicated Mini-Game script.
