It would appear it's impossible to get virtualbox guest additions working in a windows 7 host running vbox 4.1.14 and an ubuntu 12.04 32-bit guest.
I've tried the standard .iso, the .run file, and the official ubuntu virtualbox-ose-guest packages.. none of them allow me to turn on seamless mode or use copy/paste.
Any help would be much appreciated!
This works for me - with reservations! I obeyed all the standard instructions from the documentation (update, upgrade, install dkms, reboot, then install Guest Additions and reboot again).
The problems start in Full Screen or Seamless mode where it appears the the screen refresh is broken - for example you get up a Terminal and start typing - nothing happens. Click OUTSIDE the terminal and all your typing magically appears. Reverting to windowed mode fixes this and the system works including cut and paste between Windows and Ubuntu.