From what I see, you need the Easy Search utility to install the BT client. Where might one find the latest BT client, the last one on www.dlink.com is still dated 2008. I see beta release notes for 4.7.0.0, but I can't find a download link.
On another note, I attempted to install the 4.4 Easy Search BT client, all seemed to go as planned, but after the restart there is still no BT client or folder.