You do *not* typically want DHCP enabled on the apex. You want it to be the same forever and ever, because if you use DDNS to connect to your apex from outside your network (ie your iphone) you have to use port forwarding to take a port number and forward it to a specific IP. If your apex keeps getting new IP addresses every time it connects, your router won't know what IP address to send the request from the port to.
I'm not using a game adapter, I'm using a linksys WRT54g2 that has DDWRT on it. It's in wireless bridge mode.
This sounds to me like more of a configuration issue on the gaming adapter than on the router or the apex. Give static-ip a try and see if that resolves it. I've noticed that since iphones constantly get on/off the network that if you use DHCP, sometimes there is some confusion amongst devices and subsequently stuff doesn't work correctly.