Error message
In the message, %s marks a value that the engine fills in when it raises the error.
The story
You named a database with a word that rush already uses as a verb, and rush refused the name. Here is the reasoning. Databases are used through data dot, followed by the database's name. So a database called clients is data dot clients. But data already has doors of its own: data dot add, data dot remove, and the rest of the verb family. Now imagine a database named add. Does data dot add mean the door, or your database? Nobody could tell, so the rule is firm: no collision with the verb set, full stop. Rush reads the list of verbs from its own verb law, the same one it uses for its builtins, so the list never goes stale. The word default is the one exception, because it is not a verb and it is always a database. The message tells you the name and the clash, and the fix is to rename your database. Pick a noun, like orders or clients, instead of a verb. Then the door and the database each keep their own meaning.
Text from the Rush engine's error catalogue.