Try switching the fire and wait lines. The wait is there to “wait” until the fire has been sent, and then execute the command. Not the other way around.
Since I have access to the whole script Anon was using, I’ll post the solution here for anyone else having a similar problem.
When calling Knit.CreateSignal(), it does not create a Signal class that’s packaged with Knit or that’s a part of RobloxUtil, it creates a RemoteSignal class.
The error is being thrown because RemoteSignal does not implement :Wait().