What's your phone Brand and model?
I guess your phone is locked to particular Network.That's why your phone shows "Emergency calls only" error message.To solve this problem you need to have unlock your phone.You can unlock your phone using unlock code.Unlock code is the best and safest way to unlock phone.You can get the unlock code for your phone from your Network service provider or any third party online vendors like http://www.simpleunlocking.com/supported-phones/rs16wp7/ here you need to specify your country,current Network name,IMEI number of your phone.Then they deliver unlock code to you through mail with unlocking instructions.By using this you can unlock your phone easily.
sahana
September 2013