Hmmm.
I think the section should read as follows:
For Each attSub In msgInternal.Attachments 
                    If Right(attSub.Filename, 3) = "pdf" Then 
                        strAttachFName = FileNameUnique("C:\Test\", attSub.FileName, "pdf") 
                        attCurrent.SaveAsFile tempFolder & strAttachFName 
                    End If 
                Next