PDFFileEditor Append Not Working

I tried using two of the Append method overloads of the PDFFileEditor Class and neither one was recognized as a valid call. I tried:

.Append(inputFile As String, portFilesAs String(), startPage As Integer, endPage As Integer, outputFile As String)

And

.Append(inputStream as Stream, portStream As Stream(),  startPage As Integer, endPage As Integer, outputStream As Stream)

Both calls generate a compile time error saying Overload resolution failed because no accessible Append can be called with these arguments.

How do I use these overloads that are used in the docs? Thanks!

Sincerely,
Denis J. Lanza
Sr. Software Developer
Laticrete International