After the client registers/authenticates, the IP address, gateway, and DNS servers are going to come from the DHCP server. In this case the DHCP server is the a NetVanta 1234 PoE switch. The question is, is the DHCP server sending the DNS addresses in the DHCP offer or not? You could perform a traffic capture on the wired interface of the access point while you obtain an IP address (status>details>diagnostics>AP traffic capture). Then using wireshark take a look at the DHCP offer in the traffic capture to see if the DNS addresses are included. What if you put a wired client in that same vlan? Does this happen to all clients or can it be narrowed down to a specific client type such as windows XP? Check out this hotfix for windows XP where options such as DNS addresses might not get recognized on a windows XP client when the DHCP server offer included option 43:
tmcc1961, you may be mixing up DHCP for the APs and DHCP for the clients.
My apologies if this is something you know...
The APs use DHCP to get their IP address and gateway, and the APs can use option 43 to find the vWLAN server so that they can register and get their config.
The clients do not learn their DNS server(s) from the vWLAN server.
The DHCP scope for the clients subnet (vlan) would need to include the DNS server(s) which you want the clients to use.
Frequently, the AP's IP address and the clients are on different subnets, so a different DHCP scope would be involved.
If you are still having an issue, you could post your DHCP config from the 1234.
If it includes DNS servers, are those servers reachable from the client subnet? (ping, tracert)
Ken's point is also valid.