Sycthus, he is not suggesting it will not work. He is only pointing out that if you have both Wireless G and N connecting to the WAP, that the Wireless N signal will degrade unless the WAP specifically supports "simultaneous dual band". This simply means that while the WAP is connected to both signals only Wireless G will be used. The device does support both signals but not at the same time. He simply suggest that for better performance, the Wireless G devices should use your older WAP.
Thanks, Digerati - I was not aware of this limitation.