Actually, sir if you deactive data access of course you can't connect to internet :(
And are you sure you're connect to one of the Wi-Fi hotspot??
Obvious, but this appen while I set data access again on...
After I switch to wifi-mode or deactivate 3g/data access i can't connect anymore to the mobile network. The "H" or "3g" icon appear, but no one app or browser can really connect. If i reboot it work fine again...