Emial current document as a PDF using CDO from ms word with attachment using gmail

Hi i am trying below code to send my current document as a pdf with attachment but some how as its giving error message at

".Attachments.Add FileName & ".pdf" " runtime error '13' type mismatch

without " FileName & ".pdf" " its working fine but as i want to attach the exported file to send through email i am getting the above error.....  can any one please correct the code so that it can work for me.... code is below....

Sub SendEmail()

Dim objCDOConfig As Object

Dim objCDOMessage As Object

Dim CurrentFolder As String

Dim FileName As String

Dim myPath As String

Dim UniqueName As Boolean

UniqueName = False

'Store Information About Word File

  myPath = ActiveDocument.FullName

  CurrentFolder = ActiveDocument.Path & ""

  FileName = ActiveDocument.Bookmarks("scno").Range.Text

   'Save As PDF Document

      ActiveDocument.ExportAsFixedFormat _

     OutputFileName:=CurrentFolder & FileName & ".pdf", _

     ExportFormat:=wdExportFormatPDF

'setting smtp gmail mail

Const cdoschema = "http://schemas.microsoft.com/cdo/configuration/"

Const cdoSendUsingPort = 2

Const cdoBasic = 1

Const cstrServer = "smtp.gmail.com"

Const cstrFrom = "***********@gmail.com"

Set objCDOConfig = CreateObject("CDO.Configuration")

With objCDOConfig.Fields

.Item("http://schemas.microsoft.com/cdo/configuration/smtpusessl") = True

        .Item("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate") = 1

        .Item("http://schemas.microsoft.com/cdo/configuration/sendusername") = "***********@gmail.com"

        .Item("http://schemas.microsoft.com/cdo/configuration/sendpassword") = "*************"

        .Item("http://schemas.microsoft.com/cdo/configuration/smtpserver") = "smtp.gmail.com"

        .Item("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2

        .Item("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 465

        .Update

End With

'setting smtp gmail complete

Set objCDOMessage = CreateObject("CDO.Message")

With objCDOMessage

Set .Configuration = objCDOConfig

.From = "KL Prepaid Time Ext."

.Sender = cstrFrom

.To = "***********@gmail.com"

.Subject = "TEMP PREPAID TIME EXT. " & ActiveDocument.Bookmarks("scno").Range.Text

.TextBody = "Prepaid Time Extension"

.Attachments.Add FileName & ".pdf"

.Send

End With

Kill FileName & "*.pdf"

End Sub