Same story for me (using a DIR655N extreme router with DHP 303 kit there are connectivity issues and frequent disconnects with the product) . I have a buisness with 3 wireless router, 5 wireless camers(950G), 4 printers, 3 computer, 1 gigabit swith (16 port), Nas Drive (dns-323)... all Producta are D_LINK and i had a Dhp-303 kit with wired camera and since i had that, when i transfert a big file from my computer to nas or nas to nas, i lost the network some time for 3 seconds and the transfert fail... on all computers. I can'nt see my nas for 3 seconds.
i disconnect the dhp-kit, and no error since 3 weeks,,,, please help me