Apple has released a Boot Camp Update for 2010 13-inch MacBook Pro. A knowledge base article says the release:
“addresses an issue that may cause the Boot Camp Control Panel applet to display a warning message when you select the brightness tab, and an issue that may result in no headphone sound.”
The article also includes instructions for applying the update and download links for both 32-bit and 64-bit versions.
UPDATE: The download links in Apple’s knowledge base article are currently nonfunctional.