Can someone who might have been down this road before tell me what is happening?

I have a CNC router mill table with Mach 3 latest version, Windows SP3, and I am using a Logitech USB game controller (latest driver distro) for a pendant, and made the coppertubing crosshair/ flat plate attachment to zero the axies, which is hooked up to a probe line. Also, I have a USB wireless adapter on the otherwise dedicated computer system, which I use to transfer nc files from a design system, and then disable whenever loading Mach3. More about my table and layout at www.liming.org/cnc especially go to page 5 which shows the probe stuff.

This all worked 99% of the time, except that on two occasions now, When I've clicked the button to lower the bit onto the flat plate to set the Z axis zero, it touched the plate all right, and kept on going. On both occasions I touched the plate to the bit so see the green "LED" come on beforehand, as I always do. I have learned to be very close to the estop switch when setting the Z axis this way.

This has now ruined two Vbits. On another thread, others commented that they have seen this happen. I have tried both the keystroke substitution software that comes with the Logitech, as well as Keygrabber and don't think either are reliable now.

Anyone know what is happening or can shed some light on the viability of these keystroke aliasers? Are probe lines just prone to getting ignored occasionally? Is a second parallel port and some switches necessary for a reliable pendant input to Mach3?