mergDoc print not working

[chelling]

I am not sure if I suddenly have the wrong syntax or mergDoc is not getting included with standalone application settings. I have tried both manually and automatically. On the iPad, the preview sheet is not displaying. This is what I am using:

put specialFolderPath("Documents")& "/Test Session.pdf" into tPdfFile
set the printPaperOrientation to "landscape"
open printing to pdf tPdfFile
print this card from 0,0 to 1024,768 into 25,25,750,550
close printing
mergDocShowPreview tPdfFile

The last time I updated this app, I had to download the MergExt from livecode.com. That is no longer an option. I have checked the user guide and release notes for LiveCode 9, but still don't see what I am missing.

Thanks in advance.