The error has to do with looking up the variable "Rtl". The "R" probably comes from a bug in Racket's reader where certain things pasted into a Windows terminal window are parsed incorrectly. Where you typed "(tl)", somehow it saw "Rtl)".
In my experience, the bug doesn't occur as long as the text I'm pasting has a newline at the end. Maybe you could try that. That is, instead of just selecting the text you want to copy, select a blank line after it too.
Alternatively, you could type everything by hand instead of pasting... but that sounds pretty painful. Hopefully you don't have to resort to that.
EDIT: I tried to reproduce that pasting issue with Racket 6.4 on Windows 10, and I don't get it anymore. You're using Racket 6.4 too, so are you using a particular version of Windows?