Keyboard light on even though preference unchecked

Please, help me turn off the keyboard light. I've unchecked the box about illuminating the keyboard in low light, but the light still comes on. I've set the light to go off after 5 seconds of inactivity, but that doesn't prevent the light from using battery power when I'm typing, such as now. The low light preference worked fine in 10.6. I have a 2.66 GHz Macbook Pro with 8GB RAM. I'm running 10.7.3 now.