Not sure about your router, but I know when I was trying to set up these cameras at work a while back there was an issue because our internal wired LAN was on the 10.1.20.xxx subnet and the wireless is on the 10.1.21.xxx subnet and that caused issues with trying to connect to wireless after unplugging. This MIGHT be the cause for you but I'm just speculating. If you haven't you should try assigning it a static IP outside of your DHCP range on your router.
At home on my network I have had no issues connecting to wireless with 3 of these cameras, pretty much plug and play. But yea, just try assigning a static IP instead of letting DHCP handle it.