Airport Extreme on Macbookpro

Hi first off id better say hello had the mac about 2 weeks now and up till now loving it and wish id switched sooner.

i have just bought an airport extreme router and can't seem to upgrade my airport utility firstly when it arrived the installation cd was broken.

i currently have utility version 4.2.3 all is working but cant edit security settings im trying to update to the latest utility version but everytime i download an update it says i need to install 5.0 first can you point me in the right direction as cant seem to find it anywhere

cheer steve

dont worry sorted this back to loving it cant seem to get it to work on xp based desktop oh well