Error message
In the message, %s marks a value that the engine fills in when it raises the error.
The story
The engine refused to start because the document describing who may do what could not be used. In rush, powers are separated. The lawmaker makes the law, but never executes. The workers execute, but never judge and never make the law. The lawmaker is smart but passive. The worker is dumb but active, on purpose. All of this is declared in worker.feml: which powers exist, what each one holds, what each may never do, and the order of the worker's single move. This time, the engine could not read the file, or the file named no power, no step, or two steps in the same position. Why does the order matter so much? Because the worker's dumbness is a guarantee only if the verdict comes first and the work comes after. If the declaration cannot say which step precedes which, nobody can promise the work is reached only after the judgment. Picture a court where the sentence might be carried out before the trial. The engine will not guess, so it stops. Fix worker.feml, and make sure every step has its own position.
Text from the Rush engine's error catalogue.