Help - duplicate emails sent from my application

Hi - sorry if I have posted this in the wrong place! - I'm new here

Any pointers would really be appreciated - thank you in advance

I am self taught so my code is probably fairly crappy - be gentle!!

I have a aspx web page that uses vb to send an email. The problem is that sometime it sends 1 copy or more (worst up to five) copies of the same email which as the attachment is approx. 1mb makes me a little unpopular let alone not being professional. What am I doing wrong.

My code (slightly edited to protect confidentiality ) is below

The email send bit is here
'Email creation
If File.Exists(fl) = TrueThen
Dim mail As NewMailMessage()
'set the addresses
mail.From = NewMailAddress(valid email address here)
mail.To.Add(reportparam3)
mail.Bcc.Add("valid email address here")

'set the content
mail.Subject = "subject"
Dim mailmessage AsString

'add an attachment from the filesystem
mail.Attachments.Add(NewAttachment("e:\web\xxx\htdocs\tempreportstore\" & filename))
Dim smtpmail AsNewSmtpClient
smtpmail.Host = "localhost"
smtpmail.Send(mail)

the whole page code here
ProtectedSub Page_Load(ByVal sender AsObject, ByVal e As System.EventArgs) HandlesMe.Load
IfNot Page.IsPostBack Then
'Configure data sources
Me.ReportViewer_CT2.LocalReport.DataSources.Clear()
Dim rds AsReportDataSource = NewReportDataSource("rptds_getresult", Me.SqlDataSource_getresults)
Me.ReportViewer_CT2.LocalReport.DataSources.Add(rds)
Dim rds2 AsReportDataSource = NewReportDataSource("rptds_getpersonaverage", Me.SqlDataSource_getpersonaverage)
Me.ReportViewer_CT2.LocalReport.DataSources.Add(rds2)
AddHandler ReportViewer_CT2.LocalReport.SubreportProcessing, AddressOf JDASubreportProcessingEventHandler
Dim reportparam1, reportparam2, reportparam3, reportparam4, reportparam5 AsString
reportparam1 = Request.QueryString("ddddddd")
reportparam2 = Request.QueryString("name")
reportparam3 = Trim(Request.QueryString("email"))
reportparam4 = Request.QueryString("pfilename")
reportparam5 = Request.QueryString("xxxxx") 'newsletter
Dim p(2) AsReportParameter
p(0) = NewReportParameter("rpt_p_intperson_obj_no", reportparam1)
p(1) = NewReportParameter("rpt_p_name", reportparam2)
Me.ReportViewer_CT2.LocalReport.SetParameters({p(0), p(1)})
Dim b AsByte()
b = Me.ReportViewer_CT2.LocalReport.Render("PDF", Nothing, Nothing, Nothing, Nothing, Nothing, Nothing)
Dim getdate AsDate = Now()
Dim filedate AsString
filedate = getdate.ToString("ddMMyy")
Dim filename AsString = "abcd_" & Trim(reportparam4) & "_" & filedate & "_IC00" & Trim(reportparam1) & ".pdf"
Dim fl AsString = "e:\web\abcd\htdocs\tempreportstore\" & filename
Dim virtualDir = "\\" & filename
IfFile.Exists(fl) = TrueThen
File.Delete(fl)
EndIf
'XXXXXXXXXXXXXXXXXXXXXXXXXActivate lines below for live
Dim fs AsNewFileStream(fl, FileMode.Create)
fs.Write(b, 0, b.Length)
fs.Close()
'XXXXXXXXXXXXXXXXXXXXXX
'Email creation
IfFile.Exists(fl) = TrueThen
Dim mail AsNewMailMessage()
'set the addresses
mail.From = NewMailAddress(valid email address here)
mail.To.Add(reportparam3)
mail.Bcc.Add("valid email address here")
If reportparam1 > 50 Then
mail.Bcc.Add("valid email address here")
EndIf
'set the content
mail.Subject = "subject"
Dim mailmessage AsString
If LCase(reportparam5) = "y"Then
mailmessage = "Text."
mailmessage = mailmessage & vbCrLf & vbCrLf & "Text."
Else
mailmessage = "Text."
mailmessage = mailmessage & vbCrLf & vbCrLf & "Text."
mailmessage = mailmessage & vbCrLf & vbCrLf & "text"
'add an attachment from the filesystem
mail.Attachments.Add(NewAttachment("e:\web\xxx\htdocs\tempreportstore\" & filename))
Dim smtpmail AsNewSmtpClient
smtpmail.Host = "localhost"
smtpmail.Send(mail)
'Update dtmReportRun
Dim connectionString AsString = WebConfigurationManager.ConnectionStrings("connectionstring_xxx").ConnectionString
Dim con AsSqlConnection = NewSqlConnection(connectionString)
Dim cmd AsNewSqlCommand("sp_SetReportRunDate", con)
cmd.CommandType = CommandType.StoredProcedure
cmd.Parameters.Add("@personID", SqlDbType.VarChar, 10).Value = Trim(reportparam1)
Try
cmd.Connection.Open()
cmd.ExecuteNonQuery()
Catch ex AsException
EndTry
cmd.Connection.Close()
'End Update dtmReportRun
Response.Redirect("http://valid address)
EndIf
EndIf
EndSub