Currently Being ModeratedFeb 10, 2013 5:51 AM (in response to Briolet)
I just reinstalled version 6.1 There the + works, but not on the 6.2 Utility.
And I must note how unfriendly the installer is. I downloaded the 6.1 Utillity, but the installer refused to install the 6.1 utility because a newer one existed. It just does not matter if that newer version is buggy. Thank to the Pacifist installer, I could re-install a working version. It becomes time that Apple tests its applications before releasing a new update.
Currently Being ModeratedMay 19, 2013 5:41 AM (in response to Briolet)
Today I found the reason for all the problems.:
I had a DHCP range of 10.0.1.1 until 10.0.1.200. The airport itself had an IP of 10.0.1.1. (That is inside this range). This range has then this way since I bought the device 3 years ago, and none of the different Airport Utilities had a problem with it. Now I changed the starting ponint to 10.0.1.5 and all problems are gone.
Looking in the 2009 user guide: "Apple_AirPort_Networks_Early2009" (this is stil the newest version !) I see on the scheenshot that they start with 10.0.1.2. Also leaving the airports own IP outside the dhcp range.