Can anybody help?

I have the following Vb.Net code to silently open a Solidworks drawing document and save is as a PDF file.

Imports SolidWorks.Interop.sldworks

Imports SolidWorks.Interop.swconst

Imports SolidWorks.Interop.swpublished
 

Public Class Form1
   Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
       Dim swApp As New SldWorks

       Dim longstatus As Long, longwarnings As Long

       SoldworksFileName = "C:\Users\C.A.D\3D C.A.D\SolidWorks\Samples\2000 - Test Files\2000-018.SLDDRW"

       PdfFileName = "C:\Users\Public\Documents\Temp Files\2000-018.pdf"

       swApp.DocumentVisible(False, swDocumentTypes_e.swDocDRAWING)

       oDoc = swApp.OpenDoc6(SoldworksFileName", swDocumentTypes_e.swDocDRAWING, swOpenDocOptions_e.swOpenDocOptions_Silent, "", longstatus, longwarnings)

       oDoc.SaveAs3(PdfFileName, 0, 2)

       MsgBox("Finished Creating Pdf File")

       End
   End Sub
End Class

It does not create a PDF file and I have no idea why.

Does anybody know what I am doing wrong?

Many thanks in advance!

Darren