Are the AP's in the same subnet as Controller? Is the new GW/FW IP Subnet routable with existing Wireless mgmt subnet? If the AP's are routed with a different subnet in between the controller subnet, you'll need to use domain-name ID 15 in your DHCP scope that resolves to "zonedirector" at your domain, assuming you have a DNS record entry, or you could use Option 43 with the IP or DNS name in the ascii fields to reach the controller. If DNS or DHCP options are not possible, hardcode the controller DNS name or IP address at the CLI of the AP ... set director ip xxx.xxx.xxx.xxx and <enter> and then type ... reboot <enter>. See if then comes up.