Error message
In the message, %s marks a value that the engine fills in when it raises the error.
The story
Something odd just happened: the engine tried to refuse, and the refusal had no entry in the catalogue. Let me explain why that matters. In rush, every refusal has to be catalogued in errors.feml, so that every no the engine says comes with an explanation you can read. That is a design rule, not a nicety. This time, the engine tried to raise an error id that nobody declared, or that was unplugged along the way. Picture a hospital where every emergency has a card with instructions, and suddenly an alarm rings that has no card. The alarm is real, but the instructions are missing. That is an engine bug, not a mistake in your script. The message shows the id that was not found. That is your clue. If you build the engine, the cure is to declare that id in errors.feml with a message and an explanation, or to track down why the entry was removed. If you write scripts, please report the id you saw, because you just helped complete the catalogue. A rule that every refusal can be explained only holds if nothing escapes the list, and this message is the engine saying so.
Text from the Rush engine's error catalogue.