Same scenario. On old Mach3, windows 7 PC with parallel port connected to G540, can jog at will.
On new Windows 10 laptop, latest Mach4v2 and PMDX-411 drivers, using USB port, PMDX-411 and G540, I can jog a few times on any axis and then get error about cannot communicate with Smartbob.
Requires complete restart of laptop and power off/on of G540 to get it to jog again, but then loses comm. again.
Any ideas?