Got my webbrick into a state where is says Commands Disabled in the web UI and none of the physical buttons plugged into it work.

Not sure how this happened, the last command I sent to is was

http://10.100.100.100/cfg.spi?com=LG;password:CMA3;2:

To reconfigure a mimic to an analogue output.

What does this state mean and how can it be fixed? (I have done a reset for now, but was wondering how to fix it for next time!)

Go to the advanced Tab, you may need to login. And select webbrick Mode of Normal.

The mode can be one of a small set. In holiday mode the physical inputs are disabled, makes harder for burglars.