Take a look at the .syslog file fo the router - same place as NX syslogs.
If no sessions are open, it should start the most recent locally installed version of NX.
For example:
INTEROP: Executing: D:\Program Files\Siemens\NX 10.0\ugii\ugraf.exe
Be sure this file exists.
Mark Rief
NX CAM Customer Success
Siemens PLM Software