Error message
In the message, %s marks a value that the engine fills in when it raises the error.
The story
Your engine failed before it even started, and the message talks about wiring. Let's make that simple. Every builtin is declared with a wiring field, which is the name of the function that does the real work. When the engine is born, it checks every wire. This time, one wire pointed at a function that is not in the binary. Think of a light switch on the wall with no cable behind it: you can flip it all day, and nothing happens. Here the engine refuses to even start, because it would rather tell you now than let a broken switch surprise you later. The message gives you two names: the wiring and the builtin it belongs to. That is your map. Two things can be wrong. Either the function does not exist anywhere in the source, or it exists but was not linked into the build. A typo in the wiring field is the classic cause. The fix is small: correct the name so it matches a real function, or make sure that function is compiled in. Rebuild, and the engine will wake up cleanly. It is a build problem, not a script problem, and the message is there to point straight at the loose cable.
Text from the Rush engine's error catalogue.