The SubType is a new 'feature' provided by MS because of changes made
to MS Word that allows for 'backward' compatibility with earlier
versions of Word. It is, indeed, undocumented, which is also mentioned
in the MSDN postings.

Without SubType, the application won't run on my machine. MS says this
should allow the expected process to occur on any machine with Word
2002, which is where I have a problem, as this is apparently not the
case.