HP310 portrait driver issue

I'm having difficulty getting the portrait driver to correctly work on
my 310. I've followed the installation and uninstallation directions
as carefully as possible, but continue to get only half a screen in
protrait after the install.

I've tried to join the Naviter forum to clear this up there, but have
not had my confirmation email or any response to going through the
"so you haven't gotten your confirmation email" process either, so
I'm reduced to ras. Any help is appreciated, as this thing is clearly
way smarter than I am...

-Paul