You shouldn't need to change any of the variables - the code works fine for me as is. The only thing I can think of that might help is changing:
Set wdDoc = wdApp.Documents.Open(Filename:=StrDocNm, AddToRecentFiles:=False, Visible:=False)
to:
Set wdDoc = wdApp.Documents.Open(Filename:=StrDocNm, AddToRecentFiles:=False, Visible:=True)
Other than that, try repairing the Office installation (via Programs & Features > Microsoft Office > Change in the Windows Control Panel).

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]