When you are in the NX session and this error comes up, go to File --> Help --> Log file. Now you can save the syslog from here. or just look in the syslog yourself for clues that might explain what is causing this.
That did the trick. Thanks for the help !
Had set UGII_ROUTE_UGMANAGER_MODE=FALSE in
but Tc_NX90TCIN.bat was still set to TRUE