Here's my setup:

* Widows XP x64
* VirtualBox 3.0.10
* Ubuntu 9.10 Karmic Koala

Installation of VirtualBox works, and so does installation of Karmic onto a new virtual machine. When I try to boot into the VM, however, my host system crashes blue screen style.

* Windows XP x64 + VirtualBox 2.2.4 + Ubuntu 9.04 works.
* Windows XP x64 + VirtualBox 2.2.4 + Ubuntu 9.10 works, but the Guest Additions fail to install.

Does anybody have any experience with this problem?