Well you may notice that in the Filter menu under Render there used to be a filter called Lighting Effects. Unfortunately in CS5 this filter will not work in 64-bit mode. You need to go to the application folder and locate the Adobe Photoshop folder. Click on the application icon and press Command-I to get info. Then check on Open in 32-bit mode. Quit Photoshop then re-launch. The filter should be available now.