It works on Simulator but not on iPhone!

I use cocoahttpserver in my demo app for iPhone. It works well in Simulator on Mac mini. I could open the web in the browser of my PC. But when I download the app into a real iPhone, I couldn't do that. I could use safari in the same iPhone to browse the web in cocoahttpserver, but I couldn't do that on a PC. How could it work in a REAL iPhone ? Help me!