i was calling a WCF service indide an Android app , so i was still developing , so this was an Emulator Error
Unable to resolve host "XXXXX"; No address associated with hostname
The Problem here is the the Emulator does not have access to the internet or network by default. so the Solution was to go to the project manifest file and add the following line
<uses-permission android:name="android.permission.INTERNET" />
This line should be before the application section and outside the application section.