database Connection exception in data access layer code

private OracleConnection con = new OracleConnection();
        private DataSet ds = new DataSet();
        internal bool ERROR_FLAG = false;
       
       
        public Ora_DataAccess(string ConnectionString)
        {
            try
            {
                con.ConnectionString = ConnectionString;
                //con.ConnectionString = ConfigurationManager.ConnectionStrings[""].ToString();
            }
            catch (Exception ex)
            {
            }
        }

public bool ExecuteProcedure(string Procedure, string[] ColumnNames, OracleDbType[] DataType, object[] Values)
{
    ERROR_FLAG = false;
    OracleCommand cmd = null;
    try
    {
        if (con.State != System.Data.ConnectionState.Open)
            con.Open();
        cmd = new OracleCommand();
        cmd.CommandType = CommandType.StoredProcedure;
        for (int i = 0; i < ColumnNames.Length; i++)
        {
            cmd.Parameters.Add("@" + ColumnNames.GetValue(i).ToString(), (OracleDbType)DataType.GetValue(i));
            cmd.Parameters[i].Value = Values.GetValue(i);
        }
        cmd.Connection = con;
        cmd.CommandText = Procedure;
        if (cmd.ExecuteNonQuery() > 0)
        {
            cmd.Dispose();

            return (true);
        }
        else
        {
            cmd.Dispose();

            return (true);
        }
    }
    catch (Exception ex)
    {
        ERROR_FLAG = true;
        return (false);
    }
    finally
    {
        if (cmd != null)
            cmd.Dispose();
 
        if (con.State == ConnectionState.Open)
            con.Close();
        DataType = null;
        Values = null;
        ColumnNames = null;
    }
}