Need a little help- cutting a square

I am trying to engrave a square. Just 4 lines 6" at 90 degrees, with a 1/4" bit.

I can cut this on my cnc manually. But when I use easel I the gcode I make causes my cnc to cut the square as a rectangle- taller than wide. attached is the gcode.

thanks.

Untitled (1).nc (765 Bytes)

By how much?
What kind of machine do you have?