Just in case anyone's about to install this update and are also using Zone Alarm......
I installed this update today, though on rebooting, could not get my browsers to connect to the internet. The connection was okay as I could ping web sites / run tracert etc, though Firefox and IE didn't want to know.
Turns out there's some issue with Zone Alarm. After sitting for an hour trying to work this out, the Mrs (non-IT), suggested that I uninstall the Security Update. Both browsers now working fine without this latest update.
Just google KB951748, and you'll find lots of entries for this problem. Not sure if there is a resolution for this, but wanted to warn any ZA users.