Singleplayer permission issue

I have a map from late Beta, stil working on it from time to time but I have noticed that since the introduction of the command blocks and LAN-option, I no longer have permission to perform certain command. This affects mostly the command blocks themselves.

Though I am in Creative, am the only player and haven't had the map published, whenever I try to use the Command Block, it says I don't have permission to use them. For god, I have no idea what to do about this.