C# .NET 2.0
whats wrong with my code please?
I get an error on the second line saying "NullReferenceException was
unhandled by user code" - "Object reference not set to an instance of
an object."

01 string sql = "select * from myTable";
02 DataTable dtStructure = MyDatabase.ExecuteDataTable(sql);


here is my function in another class, DAL.Database
public DataTable ExecuteDataTable(string sql)
{
	// Conn and Cmd are publics
	Cmd.CommandType = CommandType.Text;
	Cmd.CommandText = sql;

	SqlDataAdapter sqlAdapter = new SqlDataAdapter(Cmd);

	DataTable dt = new DataTable("myTable");
	sqlAdapter.Fill(dt);

	//close our connection
	Conn.Close();

	//return our DataTable
	return dt;
}