I know nothing about airport cards and very little about macs. However, since you says its not working static, and if you can verify that other macs are connecting and getting dhcp, it might be a client side issue. Try rebuilding the the tcp/ip preferences and rebooting. In case you don't know how to do this, goto your hard driver, system folder, preferences folder, then move the tcp/ip preferences file to the trash. I find it best to reboot then and reset the tcp/ip settings, turn off load only when needed in the advanced options and reboot again.