AirPort can"t be installed on this disk. The version of Mac OS X on this volume is not supported. Can anyone help me out?

You will need up update the firmware on the Tim Capsule in order for it to work on newer operating systems.

Unfortunately, to update the firmware, you will need.....or be able to borrow.....an older version of AirPort Utility on a Mac running Leopard (10.5.x) or Snow Leopard (10.6.x). A PC with AirPort Utility for Windows installed on the device should work as well.

Once the firmware has been updated, then the Time Capsule will operate on current and recent Mac operating systems.

Can you clarify what exactly you are trying to do that generates this message?

IF....you might be trying to install AirPort Utility on your Mac....you already have the most recent version on your Mac.....and you cannot install an earlier version than you already have.

Check Finder > Applications > Utilities > AirPort Utility

I have the same problem when trying to install Airport for Time Capsule. Granted it is an old Capsule purchased in 2008 but i'd like to use it with Time Machine. Any advice?