God save us from Norton! 
How I hate it >:(
If you want more information about Norton desinstallation, I posted the ‘saga’ here.
About Kerio, I’m opening a new forum because it brings me a serious trouble. See here.
Take it easy, the update trouble is not so deep… Could you perform a manual update?
Sorry, but right now I need to solve my own troubles and I cannot think what is going on your system… 
Sorry, was a copy & paste error ;D