Open Blockland. Type "trace(1);" in console, then hit enter. Replicate error. Post "Console.log" located in your Blockland folder.
You obviously have a problem with servercmdbuybrick commandCheck and see if you have chrono's improved server_botdetect, because that affects that command. It should be fine as long as you don't do something weird.
I don't have any add-ons that would do this.