I've been trying to activate my corporate Vista Enterprise license, as I reinstalled Vista in 64 bits mode. I tried to activate online and I met this error message from Windows Activation utility:
DNS name does not exist.
First I thought that my proxy or firewall settings were wrong. However, the reason for this error is that Vista volume license images ship with a generic Product Key. You have to change this product key to match your company's MAK (Multiple Activation Key).
I changed it and Vista activation was a breeze. If only Microsoft would change the nondescript error message with something like "Your Product Key has not been set. Please enter your Volume MAK key". Maybe in SP1?