Check the contents of the start tab under the gcode tab. It's probably got some gcode in there that isn't compatible. Mine is now as follows:
; GCode generated by RepSnapper by Kulitorum
G21 ;metric is good!
G90 ;absolute positioning
T0 ;select new extruder
G92 E0 ;set extruder home
G1 E10 F1000 ;extrude a bit to get it going
G92 E0 ;reset extruder home
G28 X0 Y0 ;go home
M104 S185.0 ;set temperature
But to be honest, use Skeinforge for generating gcode. Repsnapper does a poor job of it. your output will improve substantially when you get to grips with Skeinforge.