VBA Word Application code Error 462 debug needed

We are trying to debug a sub-routine in a VBA Access Application.

The sub-routine creates a Word Application which then processes an existing Word file.

This is a sub-routine which is adding a Table of Contents to a Word document and then checking certain chapters to see if an extra page needs to be added to make the Next Chapter page a facing page. The modified file is then saved to a PDF file (which can then be printed as a hardcopy document):-

The routine is looping to submit a number of documents to this Sub.

The first run is OK and runs without errors, however subsequent (loop) runs brings up a 462 Error

See attached code...