QREP-HELP: "Printer not Valid"

Two my users of my Delphi 1.0 app (with Quickreport 1.0d) are getting the
following problems:
1. "printer not valid" message
and (not at the same time)
2. text on print shifting by almost half a page width to the right hand
side, so the right half of the text is off the page and not printed
3. preview showing page size as American legal size
Each problem appears unpredictably and is, sometimes, fixed by
reinstalling the app program.  All pages are set to A4 and so are the
printers (laser jets, both HP, but different models.  users are
understandably very concerned as they cannot get reports printed.
Help and thanks in anticipation.
Mike Higney