hello.
I work with Rhino and Sketchup as well.
Can you please tell me your Sketchup and Rhino Versions?
If you have a heavy file to export from Rhino to Sketchup, it will probably crash rhino.
For that, try to export small parts from your rhino model.
If this wont work, try to export in COLLADA extension from Rhino and uncheck merge faces. With this method you will not loose created groups but loose reference point.
I hope it will help you