After I upgraded to Lion, and downloaded the driver, all was well until I tried using any application in the CS5 suite. None would load. I went back to Snow Leopard. Then being a brave soul, I tried again. At first the CS5 apps worked, and then today I had the same problem. I would get the splash screen, and then the app would just shut itself down.
The clue to the problem was Photoshop, which gave a message about video drivers.
Photoshop has encountered a problem with the display driver, and has temporarily disabled GPU enhancements. Check the video card manufacturer’s website for the latest software.
GPU enhancements can be enabled in the Performance panel of Preferences.
When I unplugged the monitor on the Display Link adapter, the apps all loaded okay. When I loaded them with the adapter plugged in, they failed. I swapped monitors, so the monitor with the menu bar was the one plugged into the video of my mac. Then, even with the DL attached, all CS5 apps are loading okay.
I don't have to go back to Snow Leopard!
I'm sharing this just in case someone else is having problems.