You need to have VNC server run as the username you want to log in as for your remote desktop. For example, if you wanted to get the remote desktop for the user 'test' you would have to start the VNC server while logged in as 'test'.
Things to keep in mind:
1) Make sure your firewall allows the port VNC server uses. By default the first instance runs on port 5901 (unless you changed this). Then if a second user starts an instance of VNC it runs under port 5902 exclusively for that user. So be aware of what port its listening on and make sure the firewall allows access to that port.
2) If you shut down VNC server while logged in as root BEFORE you turn it on under another user then it will only listen on port 5901.
Hope this helps.