We are having the exact same issue when updating PDFCreator version (Windows 10 x64) i.e. printers are wiped clean by the update and "PDFCreator was not able to repair... etc." on first run, HOWEVER in our case the pdfhelper procedure works just fine and installs the (default) printer even though the installer itself fails to recreate the printers which were previously set up.
Of course once we get the default printer up we can manually rebuild our printers (we use about 10 printers for fast profile access) but it's still a showstopper when it comes to updating. Which is a shame.
Any tests we can run to help you diagnose the issue?
(Thank you for a great product by the way.)