That looks right without double checking everything.
Your plunge rate is too high, but that should cause your problem. Max z rate is 8.7mm/s, working speed is much slower (2-4mm/s) unless you are using my beta firmware.
Can you cut and paste your first 30 or so lines of the gcode.
All of your other movements are the correct distance?
Are you using the the hardware bought from here? If not, what board, drivers, step rate, pulley size?