Iphone 4s hotspot no internet access

[shz]

Hi,

I just got an iPhone 4s (os 5.0, carrier Fido), and I got a problem with internet tethering. My plan includes tethering as I am able to turn on Personal Hotspot. My pc and tablet are able to connect to iPhone through wi-fi and usb, but it shows "no internet access" with an exclamation mark. I wonder where the problem is.

Any idea is highly appreciated.

shz