G-Code xyz 0 setup

I am trying to setup the XYZ 0 for the piece that I am trying to cut.
It looks like the only way to set my ZERO point is by shooting down and powering up the machine. Otherwise it recognizes only the last ZERO point that was setup.
I tried to issue a G92X0Y0Z0 from the Repetier Host with negative results.
Does anyone have this problem?
Any tip how can I solve this??
Thank you!

I reset the arduino, but if you don’t want to do that. Try a a space after the G92 X0 Y0 Z0

Thank you!
Yes it works!

In addition, on the PC Repetier you can type the code in upper or lower case. On a MAC, it doesn’t recognize lower case. FYI.