From what I've read about this router it may require a firmware update in order work with Windows 7 and apparently you can't update using the D-link firmware unless you are on an XP machine, this is probably due to IE in XP having more relaxed restrictions on what type of files can be run. This is just what a read about this router so not sure.
It also appears that dd-WRT has some firmware that is made to work on this router and from what I have read, it works much better than D-link's firmware.
You can find this firmware in the link below, you need to know the router's exact version number to get the correct firmware. Just type DIR into the search. Router Database | www.dd-wrt.com