Error message
In the message, %s marks a value that the engine fills in when it raises the error.
The story
Multiplying text by a number is a little comfort feature in rush. The word ab times three is ababab. Easy. But the count has to make sense: a whole number, zero or more. What would two and a half repetitions mean? Half of a letter? And what would negative three repetitions look like, un-writing text? Those are not repetitions at all. The engine could round the count or clamp it to zero, but that would mean quietly doing something different from what you wrote. So it refuses, and shows you the text and the count you gave. Say you computed the count from a division and got a fractional result: that is exactly how this refusal shows up. The fix is to make sure the count is a whole, non-negative number before you multiply. Round it yourself, on purpose, if rounding is what you want. And a reminder: text plus a number is still refused. Times repeats, plus does not mix. Keep each operator doing its own job.
Text from the Rush engine's error catalogue.