Why does it says timeout when connecting to the wireless network

The problem is Enabling Guest Network Causes "Connection Timeout" issues for main network

I purchased a 1TB Time Capsule (MB765AM/A) and it has the 7.4.2 firmware on it. It seems that whenever I enable the guest networking feature, I can no longer connect to my main SSID. I just keep getting "Connection Timeout" messages, although all 3 SSIDs (I have the 5 GHz band use a separate SSID name) show up just fine. When I disable the guest networking, both of the other SSIDs work just fine in terms of connecting.

I am using fairly long WPA2 passphrases for both the main and guest SSIDs. I have tried connecting with two iPhones, Macmini, MacBook, and a iMac) running Mac OS X 10.5 and 10.6, and an Air Port Express (wireless client mode) and all can't connect to the main SSID with guest networking enabled.

this seems like it is a software bug not a hardware issue. Any ideas?