[C#] Errore OleDbCommand.ExecuteReader()

[Andriy08]

Posto un può di codice sperando che si riesce a capire meglio l'errore.

public class DataConnection
{
    private readonly Queue[list=1] m_connectionPool = new Queue[list=1]();
    private string connString;

    public DataConnection(string connString)
    {
        this.connString = connString;
    }

    private OleDbConnection GetSqlConnection(out bool isNewConnection)
    {
        OleDbConnection conn = null;
        lock (m_connectionPool)
        {
            if (m_connectionPool.Count > 0)
            {
                conn = m_connectionPool.Dequeue();
            }
        }
        if (conn == null)
        {
            isNewConnection = true;
            conn = new OleDbConnection(connString);
            conn.Open();
        }
        else
        {
            isNewConnection = false;
        }
        return conn;
    }

    private void ReleaseConnection(OleDbConnection conn)
    {
        lock (m_connectionPool)
        {
            m_connectionPool.Enqueue(conn);
        }
    }

    public void ExecuteSelect(string sqlCommand, QueryCallback callback)
    {
        OleDbConnection conn = null;
        bool repeat = false;
        do
        {
            bool isNewConnection = true;
            try
            {
                conn = GetSqlConnection(out isNewConnection);
                OleDbCommand cmd = new OleDbCommand(sqlCommand, conn);
                OleDbDataReader reader = cmd.ExecuteReader();
                callback(reader);
                reader.Close();
                ReleaseConnection(conn);
                repeat = false;
            }
            catch (Exception e)
            {
                if (conn != null)
                    conn.Close();
                if (!isNewConnection)
                    repeat = true;
                System.Windows.Forms.MessageBox.Show(e.ToString(), "Error");
            }
        } while (repeat);
    }
} 

Qualche idea?