Invalid column executing a linq with entityframework

[revotk]

I created this class\[code\]public class Usuario{ #region Atributos private int _intID = 0; private Perfil _Perfil_FK = null; private String _strNombre = ""; private String _strPassword = ""; #endregion #region Propiedades public int ID { get { return _intID; } set { _intID = value; } } public virtual Perfil Perfil_FK { get { return _Perfil_FK; } set { _Perfil_FK = value; } } public String Nombre { get { return _strNombre; } set { _strNombre = value; } } public String Password { get { return _strPassword; } set { _strPassword = value; } } #endregion}\[/code\]In my context I defined this properties\[code\]protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder){ modelBuilder.Conventions.Remove<PluralizingEntitySetNameConvention>(); base.OnModelCreating(modelBuilder);} \[/code\]and in some part of my code i do this linq \[code\]Usuario user = (from U in _db.Usuario where ((U.Nombre == model.UserName) && (U.Password == encripPassword)) select U).First();\[/code\]Resulting in this exepcion \[code\]System.Data.SqlClient.SqlException: Invalid column name 'Perfil_FK_ID'.\[/code\] What Could be the problem?, for me the code it's