In the info.plist you can include the key "UIRequiresPersistentWiFi" with a value of BOOL YES to fix this problem.
This prevents the wifi from disconnecting after 30 minutes. See http://developer.apple.com/library/ios/documentation/general/Reference/InfoPlistKeyReference/Articles/iPhoneOSKeys.html#//apple_ref/doc/uid/TP40009252-SW12
I looked in your info.plist and did not see this setting.
The setting is there in 0.6.1 , so this ticket should be closed.