I cannot activate the screen saver. My operating system is Mac OS X version 10.6.8. The screen message says 'Please contact the vendor to get a newer version of the screen saver'

To begin with, you have the wrong forum - the iMacs covered by this forum were discontinued in 2005 and are incapable of running OS X 10.6.x

Try either iMac (Intel) or Snow Leopard forums.

To get more help, contributors will need to know what screensaver you're trying to use - is it one downloaded from the internet or one of the OS X default set?

claytonfromwa wrote:

Please contact the vendor to get a newer version of the screen saver

Open your System Preferences > Desktop and ScreenSaver > ScreenSaver, find out the name of the selected screensaver, find the vendor where you got it and install the updated version, or remove it from your User/Library/Screensavers folder and reboot.