#10 envelope print positions are wrong

I have an HP DeskJet 870Cxi printer, and, aside from the
odd blank envelope (typically the initial print attempt)
when printing from Word 97/Windows 98, I have always been
able to eventually get a #10 envelope printed with the
return and delivery addresses printed in the correct
locations on the envelope.
Now, with the printer attached to a Win XP machine's
LPT1, using the print driver supplied with XP for my
specific printer and Word 2000, I consistently get the
return and delivery addresses printed offset to the right
by 3 1/4 inches.
I have checked and double-checked the envelope print
options in Word 2000 - they are identical to those I use
in Word 97 on a Win 98 machine which uses the XP
machine's shared printer as a network printer. The Word
97/Win 98 machine prints the envelopes correctly - the
Word 2000/Win XP machine simply will not.
I have searched this issue at HP and MS and can only
conclude that the Win XP supplied driver has a glitch of
some sort.
Anyone seen this problem before?