vs2003 smtpmailer sending from localhost fails sometimes

I am having the strangest problem. I have a VS2003 application that allows users to send a mail to multiple sources. The application works but it seems that the mail from my application is only being sent some of the time. On the test environment the mail is sent every time but on production it fails sometimes, but when users try to sent the mail later they are successful. Can anyone suggest a reason for this i suspect it may be a problem with my server settings but i do not know what that may be. The error generated is below.

Server Error in '/PurchasingDept/rfqapp4' Application.

At least one recipient is required, but none were found.

Description: An unhandled exception occurred during the execution of the current web     request. Please review the stack trace for more information about the error and where it     originated in the code. 

Exception Details: System.Runtime.InteropServices.COMException: At least one recipient is required, but none were found. 

Source Error: 


Line 248:               ucDlgBox.ShowError("Mail failed!",
Line 249:                   "The Rfq mail has not been sent.<br>" +
Line 250:                   "Please contact the <a href='mailto:webmaster@guysuco.com'>" +
Line 251:                   "webmaster</a> referring to quote number " + gstrRFQNo + ".");
Line 252:       }

Source File: \\webtest\sites\intranet\purchasingdept\rfqapp4\managerfq\view.aspx.cs        Line: 250 

Stack Trace: 


[COMException (0x8004020c): At least one recipient is required, but none were found.
]

[TargetInvocationException: Exception has been thrown by the target of an invocation.]
   System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object     target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters) +0
   System.RuntimeType.InvokeMember(String name, BindingFlags invokeAttr, Binder binder,     Object target, Object[] args, ParameterModifier[] modifiers, CultureInfo culture, String[]     namedParameters) +468
   System.Web.Mail.LateBoundAccessHelper.CallMethod(Object obj, String methodName, Object[] args) +58

[HttpException (0x80004005): Could not access 'CDO.Message' object.]
   System.Web.Mail.LateBoundAccessHelper.CallMethod(Object obj, String methodName, Object[] args) +112
   System.Web.Mail.CdoSysHelper.Send(MailMessage message) +1565
   System.Web.Mail.SmtpMail.Send(MailMessage message) +150
   Guysuco.RFQApp.Upgrade.MailRFQ.MailRFQToVendors2(String strFile, DataTable dtVendors) in e:\projects\guysuco.rfqapp.upgrade\mailrfq.cs:94
   Guysuco.RFQApp.Upgrade.MailRFQ.MailRFQ2(String RfqNoticeFile, String username, DateTime timeStamp) in e:\projects\guysuco.rfqapp.upgrade\mailrfq.cs:45
   Guysuco.RfqApp.managerfq.view.btnSend_Click(Object sender, EventArgs e) in     \\webtest\sites\intranet\purchasingdept\rfqapp4\managerfq\view.aspx.cs:250
   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +108
     System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +57
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +18
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +33
   System.Web.UI.Page.ProcessRequestMain() +1292