running mini display port to vga adapter firmware update

vga adapter is plugged in, and on and projecting. I run update and get message "The Updater could not find a Mini DisplayPort to VGA Adapter to update." ideas? I get a flicker on some newer displays (older ones are still working fine)using this adapter, so I thought this firmware update might do the trick. Perhaps the hardware is failing? It's about 3 yr old macbook air 2.13Ghz Intel core 2 duo, w/ 10.8.4 OSx.

Graphics NVIDIA GeForce 320M 256 MB

Thanks in advance for any help