Are you sure you included it in the form ..?

VB Code:
  1. '// CHECK FILE EXISTS FSO METHOD

  2. Public Function DoesFileExist(ByVal Filename As String) As _

  3.     Boolean

  4.     Dim objFso 'As FileSystemObject (reference)

  5.     On Error Resume Next

  6.     Set objFso = CreateObject("Scripting.FileSystemObject")

  7.     If (objFso.FileExists(Filename)) Then

  8.        DoesFileExist = True

  9.     End If

  10.     Set objFso = Nothing

  11. End Function

Can you post your code?