It works for me fine in Putty, except that it doesn't change colors.  But then, I am telnetting into a Linux box, NOT BSD.

Did you read the Important Note, in red, at the top, which says to run it in an xterm (Linux) or 'cmd' shell (Windows)?  Those are the two OS's that I tested the script on.

Also, did you make sure to change the size of the window first?