Axis 3 is A axis, Axis 4 is B axis. Try enabling all axes and see if it works

Enabling all axis' allows the pendant to work, (kind of)  the command waits until all axis arrive at home position, so it never completes. 

Also Mach4 throughs some errors, saying I need to assign a Motor to Axis 5, 
I am using motors 0-5 for X, Y, Z, A  (Y Using M1 and M3)   So I am assigning M6 to Axis 5 and Mach doesn't recognize that as a valid motor for some reason, maybe because ESS only supports 5 ?  as a test, I removed M3 from Y Slave, and assign to Axis 5, the error goes away. but can't run it like that, 

So it appears that mcCntlGotoZero(inst = 0) (unknown caller)  executes zero of all Axis X,Y,A,B,C and then the Z regardless if they are enabled or not. So it appears that this command can only be used if all axis are configured and functional.

So I have learned a lot but it doesnt appear i can use this function in the pendant the way the API functions, would be nice if it only executed the moves for Axis; that are enabled.