Yes, I copied the entire project folder. Now I've tried to open it again after deleting the Library folder but te problem remains. In the new computer, the "Open RoboDK File" button  (in the RoboDK Interface script) doesn't work, althought I have updated the robodk .exe and .rdk paths. 

When I open the project, it appears only a message in the console containing the old PC path (it is white, not a red error) saying: 

No Spacenavigator installed
UnityEngine.Debug:Log(Object)
SpaceNavigatorDriver.SpaceNavigatorWindows:.ctor() (at [old path...]/Assets/game4automation/private/RuntimeUI/SpaceNavigator/Plugins/SpaceNavigatorWindows.cs:58)
SpaceNavigatorDriver.SpaceNavigatorWindows:get_SubInstance() (at [old path...]/Assets/game4automation/private/RuntimeUI/SpaceNavigator/Plugins/SpaceNavigatorWindows.cs:63)
SpaceNavigatorDriver.SpaceNavigator:get_Instance() (at [old path...]/Assets/game4automation/private/RuntimeUI/SpaceNavigator/Plugins/SpaceNavigator.cs:37)
SpaceNavigatorDriver.SpaceNavigator:get_Translation() (at [old path...]/Assets/game4automation/private/RuntimeUI/SpaceNavigator/Plugins/SpaceNavigator.cs:13)
SpaceNavigatorDriver.ViewportController:Update() (at [old path...]/Assets/game4automation/private/RuntimeUI/SpaceNavigator/Editor/ViewportController.cs:72)
UnityEditor.EditorApplication:Internal_CallUpdateFunctions()