I'd check firewall permissions. When I first fired up the Airdroid desktop client, the Windows FW asked me to give the client permission to access the web. I did that and it worked like a charm, no need to run as administrator or anything else (note that I have an admin-level login anyway though).
BTW, the desktop client is nothing special. I'll probably stick mostly to the web server version which has more features.
BTW, the desktop client is nothing special. I'll probably stick mostly to the web server version which has more features.