I have a problem with kuka sim 4.0. After I have made some positions in Program and want to play it I get this error message: visual component unhandled exception on initializing KRL + value cannot be null + parameter name: node.
I have deleted the positions again and checked through various folders for syntax error, without it helping the problem.
Please report any errors and exceptions regarding kuka sim directly to kuka sim technical support.
In any case, make sure you use robot from KUKA.Sim eCatalog. Those robots have specific properties and behaviors to work with tools in KUKA.Sim, e.g. KRL Executor behavior.