it's set up as a wireless bridge that connects to my DIR-825 which is not running as a router either
So DAP-1522 is connected via wireless bridge to you DIR-825:
By Default DAP-1522: 192.168.0.50
By Default DIR-825: 192.168.0.1
What is the 825 connected to if it is acting as an AP? Also do you have DHCP disabled on the 825 if you are using this as an AP?
If you disable QoS on the 1522 does your 360 start to communicate with other machines on your network?