As soon as I added this update, I no longer had access to my network shares. I doublechecked everything, and also changed my computer browser service in Windows 7 from manual to automatic. Still no shares. I rolled back to the previous firmware update, and now everything works again. Have set my WDTV Live to no longer automatically check for updates.
I actually had 2 problems. The firmware plus my computer browser service not being in automatic mode.