Multiple-step OLE DB operation generated errors

while (!rds.EOF)
            {
                if (loanDate >= DateTime.Parse(rds.Fields["startdate"].Value.ToString()) && loanDate < DateTime.Parse(rds.Fields["maturitydate"].Value.ToString()))
                    rds.Fields["inCash"].Value = rds.Fields["notional"].Value.ToString();
                rds.MoveNext();
            }

using System;
using System.Collections.Generic;
using Microsoft.Office.Tools.Excel;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Data.Odbc;
using System.Data;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using Excel = Microsoft.Office.Interop.Excel;
using Range = Microsoft.Office.Interop.Excel.Range;
using Worksheet = Microsoft.Office.Interop.Excel.Worksheet;

// Fred Liu. Thursday June 14, 2012-Friday June 15, 2012

namespace Fills2010
{
    public class Loans
    {
        public Loans(BookRangeSettings sett, SqlDataTools sqltools)
        {
            try
            {
                m_xl = sett;
                m_dataTools = sqltools;
                printLoans("abc", "1");
                printLoans("abc", "2");
                printLoans("abc", "3");
                printLoans("abc", "4");
            }
            catch (Exception exp)
            {
                MessageBox.Show(exp.Message + "\n Stack: " + exp.StackTrace);
            }
        }

        private void printLoans(string book, string accountBlock)
        {
            Range loansRange = m_xl.NamedRange("Loan_Output_" + accountBlock);
            Range accountRange = m_xl.NamedRange("Account_" + accountBlock);
            loansRange.ClearContents();

            DateTime loanDate = DateTime.Parse(m_xl.NamedRange("Loans_Date").Text.ToString());

            // Get the account # from the account ID
            string query = "select * from accounts"
                + " where accountname = '" + accountRange.Value2.ToString() + "'";
            ADODB.Recordset rds = m_dataTools.Query_SF(query);

            /* Book is found by trial and error with the existing data and SQL Server since the old C++ fills
             * code does not compile and it's impossible to find the values
             
             The 3 columns from the right (PnL receive, in cash, and realized interest) are pre-populated with 0s
             * here and then replaced with their appropriate values if necessary */
            query = "select startdate, maturitydate, counterparty, comment, daycount, notional, interestrate, 0 PnLReceive, 0 inCash, 0 realizedInterest"
                + " from loans l, counterparty c"
                + " where maturitydate >= '" + loanDate.ToString("MM/dd/yyyy") + "'"
                + " and accountId = '" + rds.Fields["AccountId"].Value.ToString() + "'"
                + " and book = '" + book + "'"
                + " and c.counterpartyid = l.counterpartyid"
                + " order by maturitydate";

            rds = m_dataTools.Query_SF(query);

            // Replace the last 3 columns with non-zero values if necessary

            /* ERROR OCCURS WHEN THIS BLOCK IS UNCOMMENTED
            while (!rds.EOF)
            {
                if (loanDate >= DateTime.Parse(rds.Fields["startdate"].Value.ToString()) && loanDate < DateTime.Parse(rds.Fields["maturitydate"].Value.ToString()))
                    rds.Fields["inCash"].Value = rds.Fields["notional"].Value.ToString();
                rds.MoveNext();
            } */

            ((Range)loansRange.Cells[1, 1]).CopyFromRecordset(rds, Type.Missing, Type.Missing);
            rds.Close();

            // Format the columns as the appropriate date, rows 40 to 1000
            for (int i = 40; i < 1000; i++)
            {
                Range dateColumn = (Range)(loansRange.get_Range("A1", "B500"));
                dateColumn.NumberFormat = "ddd d-MMM-yyyy";
            }
        }

        private BookRangeSettings m_xl;

        private SqlDataTools m_dataTools;
    }
}