Possible that your ISP has this on lock down if the unit came from them.
You are logging in as Admin to manage the router UI right?
The only think I know of is that if Advanced DNS is enabled then the manual DNS boxes are grayed out. At least for retail units. ISP supported units, not sure.
How did you apply the 1.09 FW? Via the UI?
Check with your ISP and see if they have any other recent updates and this maybe a unit they maintain.
If the unit is now yours, you might try doing the following:
Download most current version of FW for your region from the regional D-Link support site. You can use this one here if you choose to:
http://forums.dlink.com/index.php?topic=65889.0Follow the recover process and load the unpacked .bin file to the router at the recovery screen if you can get to this screen.
Emergency Recovery Modehmm I got it from the ISP. Tried to flash a different firmware over it (it came with 1.06SHC, i flashed the generic 1.09)...