http://ubuntuforums.org – I have VirtualBox version 3.2.8.r64453 running on Windows XP SP3. Installed as a guest is Ubuntu 10.04, which was installed a few days ago and I let the update manager fully update after the install. I then installed guest additions, and haven't had any problems. Although the last couple of days Update Manager has done "partial updates" due to an external package changing some files. (HowTos)