That's odd. it should simply work. Log into your router and look for connected devices. If your phone shows up in the list then that is even more odd, but if it isn't you know it isn't on the LAN.
If it works on your pc, it should work on your phone. You're absolutely sure you're on the same LAN? Make sure your 3 or 4 g is turned off, and only wifi is on your phone.