Help HTC Desire, Unlocked but not connecting my mobile network


My HTC Desire locked to orange has just been unlocked, everyother thing is working fine but surprisingly I can't connect my mobile network (both 3 and T-mobile)...keeps giving the message: "UNABLE TO CONNECT - You need a network connection to use this application. Please turn on mobile network or Wi-Fi in Settings"
The Wi-Fi and Mobile network have both been turn on, yet I can connect.

Will this phone ever give me internet access? This is so frustrating!