I see the link that the fine D-link forum people here posted doesn't work, much like the support you get when submitting a support ticket.
When I clicked the forum link, it took me to a page to choose my country. If this is what you get, choose your country.
-Then it took me to a page where you can search. Under "Product Support & Downloads" type SharePort and click "See All Products" .
-It will then take you to a page where you choose what cr@ppy D-link hardware you own. I unfortunately own a DIR-825 Router and a DNS-323 NAS, both that has a mainly useless USB port.
-You choose the hardware you have. It will take you to the products info page.
-In the upper right corner of the product info window(not the browser window) there is a black toolbar with the last button labeled "Support Resources"(Right below a Print button). Click that.
-You may have to more closely define the hardware version you have OR it will take you to a window with support choices. One of the choices will be "Additional Downloads". Click that and when it loads you can scroll down until you find SharePort 3 for PC or scroll for the Mac version.
I tried to add a direct link to D-Links ftp download site earlier for someone and it wouldn't work via that route. You have to take the one above. Good Luck getting your D-Link hardware to work as they claim it does on the box. You're going to need it.