How do I light up the LED1 on the G120?

How exactly do I toggle this LED? I’ve tried the following:

			
var cobra = new GHIElectronics.Gadgeteer.FEZCobra_II();
cobra.SetDebugLED(true);

but it blows up on the 1st line with the following:

Remove
cobra = new GHIElectronics.Gadgeteer.FEZCobra_II();
cobra.SetDebugLED(true);

use

Mainboard.SetDegLED(true)