Info only. Airport 5.6 works with Mountain Lion because I use it. The problem is finding it. I was able to drag from my Snow Leopard partition. Here is a link to download it.
Paul Schleuse wrote:
The solution suggested by mende1 requires AirPort Utility 5.6, which is not supported in Mountain Lion. The new version (6.1) does not include a "disconnect all users" option.
I'm having the same problem with the "sparsebundle already in use" error.