That's good news
, Now users can upgrade to windows 8 without any worries.
I, too, had to set the Java runtime file path in the user environment variable but i forgot about it.
Regarding display area: I didn't face this problem.
But display area depends on screen rotation prior to running serial_vnc.oar
If boox is in landscape mode then display area is less (14.5 cm x 13.5 cm), otherwise it covers full screen (21 cm x 14.5 cm).
Your measurements are different than these
One possible solution is to goto "Control Panel\Appearance and Personalization\Display\Screen Resolution" Here you can setup a 2nd display. Set it as "display device on : VGA" and change its resolution to match your pc resolution. (There is no mechanical switch on my laptop to turn off display; so when i want to turn off my screen and read only from boox, i put my laptop to "Projector only mode". The display area was different initially and i changed it by setting up a hypothetical 2nd display)