continuous error in date time picker in c#

string s = "2011-06-16T05:07:57+0000";

private void dateTimePicker1_ValueChanged(object sender, EventArgs e)
{
    DateTime theDateA = DateTime.Parse(s);

    if (Convert.ToDateTime(dateTimePicker1.Text)> theDateA)
    {
        MessageBox.Show("ERROR");
    }
}