Can't change Airport Extreme Stations ...

Situation:

I've got 2 Airport Extreme in my house because of the thick walls. Each AP Extreme works fine. I can change the Airport directly by selecting it on the top Button with my MacBook. But using my MBP (2,8 500 GB, the new big one) with Snow Leo it is not possible to change the Airport Extreme Station nor switching it OFF at the MBP.

Question: Do we have a bug on SL because I can not switch off the Airport Card? I reinstalled Snow Leo but it does not help. It is also not possible in system preferences (Network) to switch off the MBP's Airport Card.

Any idea? Is the hardware damaged? Is it a software problem? How to check and solve?

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Orignal From: Can't change Airport Extreme Stations ...