It seems like everyone who uses a mac has serious problems with the tcp objects in Blockland. This isn't something I can fix, I'll have to talk to Badspot about it and see how inclined he is to investigate.
The only way to make RTB work with Blockland is to remove any other add-on that uses a tcp object, so essentially re-install Blockland and then just install RTB and a few other basic add-ons. Things like the Gui Replacer which use net objects will cause everything to break.
I would recommend not using RTB until this is fixed because it'll probably just be a headache for you.