I should have asked you to turn on Timestamps and Show Raw Data in NCE Monitor so I could correlate with System Console (and get more information).
Some observations:
You launched JMRI V4.11.6 (please update to V4.12) on 2018-07-13 and JMRI successfully contacted the NCE USB and got a version number back (7.3.0). (This doesn't mean the USB had talked to the Power Cab).
Around 20 seconds later you got a "programmer in use" message. This is most likely when you pressed Identify and then didn't wait for it to finish. The Identify routine sends a Read CV29 command in direct mode and waits for a reply from the command station. If there is no reply (JMRI 306) or a loco-not-found (JMRI 301) message is ?it tries twice more in direct mode and then three times in paged mode (even slower) before restoring direct mode and giving up.
I'd you try something else in that period your JMRI session is hosed and you need to restart JMRI.
The sign of a communication failure between the NCE USB and Power Cab is the Cab Bus LED on the NCE USB coming on and sticking on (won't go off unless you unplug cab bus cable to reset microprocessor on NCE USB).
Please try again with my comments in mind, after updating, checking that nothing in Preferences->Defaults is set to Internal instead of NCE and turning of Verify after Write in Roster Programmer (it can do bad things with some decoders).
