Is there an action you can repeat to cause that error? Might help others to help you figure out where the issue is.
If it occurs with all 3 racks, maybe something is corrupt in the toolc.dat file? Remove it and then recalibrate your racks to see if that stops the error? Good luck...
I restarted the controller and the TESASTAR-R probe changer. I also made sure the probe extension's key hole (that locks the probe in) was lined up with the TESASTAR-R individual port keys. Now it works!