My X and Y are set to 1/8 and my Z is set to 1/4. MY X and Y are on a belt and my Z is on a screw.
This doesn't make sense. Your X and Y axes are set the 1/8 steps per inch (or mm)?? When you go to the Configure->Mach menu, click on the "Motors" tab and select "Motor0", what does the "Counts per unit" say? Likewise the other motors.
For "very small" jog increments, if you don't get any motion it means that the jog increment is smaller than one step as entered in the "count per unit" field referenced above. For example, if you have 100 counts per inch, each step pulse will move 0.01 inches. If you set the jog increment to 0.0001 inches and try to do an incremental jog, you will get no motion until you jog 5 times (I think the PMDX plug-in rounds fractional motion up starting at 1/2 of a step). And then every 10 incremental jogs.
Likewise, if you set the "counts per unit" to 400, each step will be 2.5 thousandths of an inch. If you start at zero and command a move to 0.008 you will actually end up at 0.00075 because that is as close as you can get with that step size. If the DRO is displaying 3 fractional digits, it will round up (I think) and show 0.008. If the DRO shows 4 fractional digits it will show the full 0.0075.
What is the message "Attempt transition from "Jogging" on event "Stop Jog" Controller.cpp:1379" indicate? Where can I find a listing of all the error messages?
This is not an error message. It simply says that the Mach4 core is attempting to change out of the "jogging" state, because it received a "stop jog" event (i.e. the motion planner told the core that it was done generating the motion).