Unless you changed to relative positioning, G1 Z-10 tells your printer to push the nozzle 10mm through your bed (z = -10) which your printer cowardly refused to do.
I'll give you a head start on what I had to learn the hard way. X=0, Y=0, Z=0 is the center of the print bed, with the nozzle touching the bed. The endstops go on top, and a home command should set X=0, Y=0, and Z=max_height after all three endstops are triggered. G1 Z10 should position the nozzle 10mm over the center of the bed. Repetier has several configuration settings that assume a Cartesian printer, where things like homing direction and steps are different for Z versus X and Y. You will need to go through and make sure that you changed them all, specifically homing direction above. I don't have my printing computer powered up to check my config against yours, so I can't comment on specific settings.....
I'll give you a head start on what I had to learn the hard way. X=0, Y=0, Z=0 is the center of the print bed, with the nozzle touching the bed. The endstops go on top, and a home command should set X=0, Y=0, and Z=max_height after all three endstops are triggered. G1 Z10 should position the nozzle 10mm over the center of the bed. Repetier has several configuration settings that assume a Cartesian printer, where things like homing direction and steps are different for Z versus X and Y. You will need to go through and make sure that you changed them all, specifically homing direction above. I don't have my printing computer powered up to check my config against yours, so I can't comment on specific settings.....