I have to run the configuration tool in a windows VM because on 10.10 they removed the frameworks it uses to run. I wish they weren't so complacent as to turn my hardware into bricks.
Maybe you just need to reinstall it? I just took a peek at it on my new laptop (which has never had anything but Yosemite installed on it) and it worked fine.
Airport Utility 5.6.1 was the last version that supported some of the older airports. Unfortunately Airport Utility 5.6.1 doesn't work (officially) on anything newer than Snow Leopard, but there's some modified versions floating around that work on 10.9