Currently Being ModeratedApr 21, 2012 10:42 AM (in response to Zapdoc)
I assume that you have likely updated Lion to 10.7.3.
Open Macintosh HD > Applications > Utiliites > AirPort Utility
Click on the AirPort Extreme icon
Click the Disks tab at the top of the window
Make sure that the setting for Secure Shared Disks = With a disk password
If you want KeyChain access on your Mac to remember the disk password, leave the box checked. If you want to enter the password for the disk each time that you connect, leave the box unchecked
Click Update at the lower right and allow 25-30 seconds for the AirPort Extreme to restart