I'm checking through the file right now, and it says this in the code:
MessageBoxYesNo("New Version Available", "There is a new version of Blockland Plus available. Do you want to download it?", "BlocklandPlusCheckUpdate(1,\"" @ %url @ "\");", "canvas.popdialog(BlocklandPlusUpdaterGUI);");
Which is strange, since the update message we're seeing is far different and more malicious in intent.
Also, the only links to any server I've found are to blocklandplus.weebly.com, which means the original file is more than likely legit.