not familiar with gcode2000, opened the file, used Kcam, got wierd reversal on 'part' of the drawing..
Converted to dxf with autocad DXB utility, came out ok..
with something simple like this, all you need is a 2d dxf, and input your Z depth directly into the nc code..
not sure if this is the answer you're looking for,,but??
enjoy..