Command Backtick isn't working to cycle through windows in some apps (including Safari)

This has bugged me since i got my MacBook but have just managed to fix it by doing this:

"going to System Prefs, Keyboard & Mouse, Keyboard Shortcuts, Keyboard Navigation, and click on Move focus to next wondow in active application. There may be other shortcuts that you can restore there, too." taken from From http://discussions.apple.com/thread.jspa?threadID=1776080:

Then change the shortcut to apple key + `

Hope this helps as I know it's such a pain not being able to quickly switch between windows, particularly in Safari.