Unable to load the specified metadata resource.driving me crazy

Unable to load the specified metadata resource.driving me crazy

I hope someone can help with this
my connection strings are as follows:
<add name="RollCallDBEntities"
connectionString="metadata=res://System.Engine/RollcallNS.csdl|res://System.Engine/RollcallNS.ssdl|res://System.Engine/RollcallNS.msl;provider=Devart.Data.Oracle;provider
connection string=&quot;User
Id=user;Password=password;Server=127.0.0.1;Direct=True;Sid=ORCL&quot;"
providerName="System.Data.EntityClient" />
my code are as follows:
using (var db= new RollCallDBEntities()) //ok
{
var query = db.TBL_ROLLCALL.ToList(); //Unable to load the
specified metadata resource.
}
my assembly:
System.Engine
Anyone have any ideas?