It might be possible that your connection is sting is malformed. (I see opening single quotes on datapath, but no closing)
A good starting point would be looking at the connectionString created in your Model's app.config file (i.e. assuming you created your model based on an existing database)
For instance, I've tried the following without any issues: (I've copied the connectionString from app.config)
EdmKeyElement edmKey = new EdmKeyElement("NorthwindIBEntities");
edmKey.Connection = "metadata=res://*/NorthwindModel.csdl|res://*/NorthwindModel.ssdl|res://*/NorthwindModel.msl;provider=System.Data.SqlClient;provider connection string='data source=.;initial catalog=NorthwindIB;integrated security=True;multipleactiveresultsets=True;App=EntityFramework'";
Also, you might want to use DataSourceExtensions.
Edited by sbelini - 01-Mar-2012 at 6:44pm