problem controlling MS Word from Python

[Andrew Brown]

    	I am ignorant and inexerienced, so I may have missed something 
obvious. Or I may have found a real bug. I have been using Python on Windows 
2000 to process a bunch of word documents, first saving them as html using 
Word itself as the translator, then removing all the Microsoft cruft from 
the resulting files; finally reformatting them into my preferred layout.

The problem I am worried about comes with the first step: when Word stops 
converting a document, complaining about the code page being wrong, the 
whole Pythonwin program (ActiveState 2.1) crashes too. Yet I thought this is 
what exceptions were meant to catch. 

Here are the relevant bits of code:

def domydir(self):
	"Processes all the .doc files in a directory using do_that_thing()"
	QApplication.setOverrideCursor(Qt.waitCursor)
	try:
		self.o=win32com.client.Dispatch('Word.Application')
		self.o.Visible=1
	except:
		warning='OLE fuckup! ' + str(sys.exc_type) + str(sys.exc_value)
		self.btn_dirpick.setText(warning)
	mypath,myfile=os.path.split(str(self.wombat_txt))
	os.chdir(mypath)
	self.o.ChangeFileOpenDirectory(mypath)
	# show what we're doing on the button
	for wombats in os.listdir(os.getcwd()):
		if string.find(wombats, 'doc')>1:
			htmlfile=self.htmlext(wombats)
			self.do_that_thing(wombats,htmlfile)
		 	print 'have just processed', htmlfile
	QApplication.restoreOverrideCursor()


And 

def do_that_thing(self,docfile,htmlfile):
	'''gets an instance of word, to save the docfile as html.'''
	try:
    		self.o.Documents.Add(docfile)
		self.o.ActiveDocument.SaveAs(htmlfile,17)
		self.o.ActiveDocument.Close()
	except:
		warn='DO that Thing! ' + str(sys.exc_type) + str(sys.exc_value)
		self.btn_dirpick.setText(warn)


I'd have thought that, since all the calls to Word are wrappred in "try" 
blocks, there should not be a problem when Word throws up a dialogue box. 
But there is. The whole thing crashes. Does anyone know why this happens, or 
how to avoid it?