runtime error '800a01f5

[truskyvb]

Antes de nada, Feliz Año!!! Mi consulta es la siguiente: Tengo un libro de firmas que unas
veces funciona y otras no.
El error que da es:

Microsoft VBScript runtime error '800a01f5'

Illegal assignment: 'FileObject'

/truskyl/Libro.asp, line 83


El error lo da en esta parte del código:

<%
Const ForReading = 1, ForWriting = 2, ForAppending = 8
Dim ThisLine, PrintLine
Set FileObject = Server.CreateObject("Scripting.FileSystemObject")
GuestBookFile = Server.MapPath("guestbook.txt")
Set InputStream = FileObject.OpenTextFile(GuestBookFile, ForReading, False)
Do While Not InputStream.AtEndOfStream
ThisLine = split(InputStream.ReadLine, "vbCrLf ")
PrintLine = "<hr>" + PrintLine

PrintLine = "<br/>" + PrintLine

For x = LBound(ThisLine) To UBound(ThisLine)

If x = UBound(ThisLine) + 1 Then
PrintLint = ThisLine(x) + "<br/>" + PrintLine
Else
PrintLine = ThisLine(x) + "<br/>" + PrintLine
End If

Next

PrintLine = "<br/>" + PrintLine

Loop

InputStream.Close
Set OutputStream = Nothing
Set FileObject = Nothing

Response.Write replace(PrintLine, "//vbReturn//", " <br> ")

%>
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Si podeis darme alguna idea os lo agradezco.

Un saludo