It looks like the command works, but possible that some of the variables are corrupted. The $22 to $27 variables shouldn’t have those extra garbage characters. Try just setting those to zero, and then to the correct value. I thing it is because of those that’s it’s printing the error:Bad number format.
Looking at the picture and your gShield from the edge that has the homing switch connector, the D8 through D13 etc. positions are where you soldered the pins for the homing switches and the spindle control. Not interested in those at the moment.
The set of holes to the left of that which has D2 through D5 labeled is what we want to look at. Just to the right of the D5 hole is D6. This is the direction signal for the Y axis.
When you jog your machine in one direction that pin will measure about 0 volts with respect to ground. When you jog the machine the other direction then you should read about 5 volts on that position.
D3 is the step pulse signal for the Y axis. When your machine is not moving this hole should be about 0 volts. When you jog the Y axis this pin will have a square wave on it and the meter should show something like 70 mV as an average.
Taking these measurements will tell you if the Arduino is trying to tell the motor to move.