Qualcuno sa risolvermi questo problema:
Perché nel momento in cui eseguo il seguente codice:

cmd.CommandText ="DELETE FROM Rubrica WHERE (Id_Voce = @IdVoce)";

cmd.Parameters.Add(new System.Data.OleDb.OleDbParameter("@IdVoce",
System.Data.OleDb.OleDbType.Integer,10));

cmd.Parameters["@IdVoce"].Value=IdVoce;


this.DBConn.Open();
this.DeleteRubrica.ExecuteNonQuery();
this.DBConn.Close();

Mi da il seguente problema sulla riga this.DeleteRubrica.ExecuteNonQuery();
:

System.Data.OleDb.OleDbException: Nessun valore predefinito per il parametro
?_1.at System.Data.OleDb.OleDbCommand.ExecuteCommandTextErrorHandling(Int32
hr)at
System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARAMS
dbParams, Object& executeResult)at System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object&
executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior
behavior, Object& executeResult)at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior
behavior, String method)at System.Data.OleDb.OleDbCommand.ExecuteNonQuery()
at RubricaWS.FunzioniWS.Cancella(Int32 IdVoce) in

c:\inetpub\wwwroot\rubricaws\dbfunzioni.asmx.cs:line 490
???
GRazie