When you run the same component set from your Cable box to your TV, does the picture still show as green? If it does, it would be an issue with the Component input from your actual set top box. If not, it is possible something has happened to the input on the Slingbox itself. Set top box issues would be pretty easily fixed by calling your TV Provider, but if the issue is with the Slingbox and the unit is still in warranty, you can reach out and have the unit replaced. I would also check to make sure the red audio cable and the red video cable are not crisscrossed into the other's input slot.
Please keep in mind that, if you go through and it appears the unit is the problem, you will still need to go through troubleshooting steps with an agent before it can be replaced.
I hope this helps!!