Trouble connecting to new d-link router via airport

[CGMac]

We just purchased a new D-link DIR-655 router. Our Windows laptop connects fine wirelessly. We are having trouble connecting our Powerbook (G4 running OS 10.4.11. I went through technical support with d-link (for 3 hours!) and at the level 3 tech support I was told I would have to call Apple to try and fix my problem. The computer will connect wirelessly when it is close to the router, but will fluctuate between 2 different IP addresses (144.3.8.0 and 192.168.0.196). When it's connected to the 192 address it is fine. When it flips to the 144 address the wireless disconnects. Has anyone else ever run into this problem? Any ideas on how to fix it or how to keep the IP address at the right one?