Well I'm kind of angry at the moment. I was relocating the extender to another room and when plugging into the receptacle both ****gs broke and are halfway inside the extender and loose. I just purchased this 3 months ago. I can still plug it in but have to hold it in place or it will fall out of the receptacle

Anyways to answer some of you questions...
The cameras are on 11n I believe if that's what you mean. WPA-WPA2 authentication. I tried using WPA2-PSK for my new DCS-2670L but for some reason it won't save with that option. My other cameras use WPA2-PSK. I was also trying different channels but nothing seemed to help. It takes a long time to connect and something it doesn't connect at all. When its working the video is laggy and freezes/disconnects constantly.
Here are all the devices connected this router. Not all are using it at once
4 PC/laptop (2 via wifi and 2 wired)
3 iPads
2 cell phones
1 TV (wifi)
1 A/V receiver (wired)
1 Blu-ray player (wifi)
1 printer (wifi)
DCS-5020L
DCS-936L (using extender)
DCS-2330L (using extender)
DCS-2670L (using extender)