hello
I have ubuntu 15.4 64bit.
I have problems in origin…Anywhere I choose At the top left is origin…
See photos above
Everything seems ok but the expression should be “ramp.PointX(Nok)” (note the capital “P”) 
When GD finds have a problem with a number expression, it uses 0 (zero) instead, then your pea will be at 0;0 = origin 