Have you hade a power-outage or -glitch? D-Link routers are a little finicky on power-dips. Just reset the router (easiest is to remove power for a minute or so, or press the reset button with a bent paperclip [no, not 'that' kind of bent]...
It looks like the DHCP is not able to hand out IP-addresses. You changed nothing on the router before this started to happen?