Only emulators can connect to server running on PC, not actual devices

I have an app that connects to a server using Sockets. If I run the app on an emulator and the server on t开发者_如何转开发he same PC, they connect just fine. If I run the app on my SGS Vibrant and try to connect to the same server on the same PC, nothing happens. The server is a standalone Java program I have written. I have disabled Windows Firewall and I haven't installed any kind of firewall on my phone. The phone and my computer are connected to the same WiFi connection. Any idea what could be causing this?