Error message
In the message, %s marks a value that the engine fills in when it raises the error.
The story
Your script has a block of lines pushed to the right, and nothing above them asked for it. In rush, indentation is structure. A deeper line belongs to the header just above it. So when an indented block appears and no header opened it, the engine says so, right on that line. A typical cause: you finished a function body, but one line stayed indented, left over from an edit. Or you deleted a header and forgot its body. Now, why does the engine stop here and not later? Because if it carried on, it would try to read those lines as part of something else, and then complain about a name, several lines away, that has nothing to do with the real problem. You would be chasing the wrong clue. Stopping at the exact line points you to the true source. The message names the block and the line. The fix is one of two simple moves. Remove the extra indentation, or put back the header that the block belongs under.
Text from the Rush engine's error catalogue.