You may have to install Fiddler2 to see what is happening with the web request to JRiver's servers. When installed, and capturing traffic, and you do an Update from Online Database, you should see a line in the output to the host
www.yadb.com, and the URL cgi-bin/CDLookup.cgi...
A successful connect will return a result of 200, and the lower right section in TextView mode will show the results.
If you get no response, or a 4xx or 5xx response, then something has blocked or interfered with the traffic.
If you're not sure what to do with this info, you could select all but the single line to
www.yadb.com, and Delete. Then, save the single request by doing a Save > Selected Sessions > in ArchiveZip... and save the file. You can either attach it here, or email it to me (I'll PM you my email). There's nothing confidential in that single request.