When trying to install Quickmap Data Download Manager, or updating registration information (like entering the key), you may get this error:

Product Registration Failed

Failed to register: Could not connect to
net.tcp://downloads.quickmap.co.nz/DataDownloadService/DataDownlaodService.svc. The connection…

This is because a firewall is blocking the connection. Check that you are not blocking (particularly inbound) TCP port 808, net.tcp, wcf, or the quickmap website (downloads.quickmap.co.nz in the case of this particular Quickmap service).