Hi guys
I might be clutching at straws here but found the following post that I was not aware of.
"It seems to be a problem with the BROADCAST flag in DHCP discovery packets. In XP its off and in Vista its on. Non Microsoft DHCP servers dont like this. See the fix on the next page;

1. Start > run > regedit.exe
2. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\Tcpip\Parameters\Interfaces\{GUID}
3. {GUID} sub-key refers to the network adapter that is having the issue. In my case my Intel Pro 2200BG card.
4. Add a new DWORD (32bit) value and rename it to DhcpConnDisableBcastFlagToggle.
5. Modify the DhcpConnDisableBcastFlagToggle key and change the value to 1″.
6. Modify the DhcpConnForceBroadcastFlag key and change the value to 0″.
7. Reboot and test the connection again with DHCP. (The reboot is optional)
Read the full article at Microsoft
Hope it helps!!!!!!!!