So you included a seperate assembly as a project in your application, which would allow you to access the classes and whatnot.
The problem is that it needs access to an endpoint address. The app.config file in your referenced DLL would have that information, however, The application configuration file of the current executing program is the one that gets used, so you'll need to copy the xml from the app.config file in your referenced assembly to your current project.
This is the block of code you're looking for.
<client>
<endpoint address="WebServiceAddress"
binding="wsHttpBinding" bindingConfiguration="GPWebService"
contract="DynamicsGP.DynamicsGP" name="GPWebService">
<identity>
<userPrincipalName value="crm@emailaddress" />
</identity>
</endpoint>
</client>