First of all I would leave it disabled. Look around the forum and you will see the problems people sometimes have with new firmware.
Obviously you found where you need to go to change the settings.
Did you uncheck the boxes next to the settings you want to change? If you haven't already done so uncheck them because you cann't change any setting that has the default check box checked.
If you still can't change the settings then go to the bottom of the page and click submit.
Return to the page and try again.