I strongly recommend following the procedure described for "Debian-based" distributions on the VirtualBox Linux download page. You'll probably also need to install the kernel headers for your release so the installer can compile the needed kernel module. Give this a try:
First, add this line to the bottom of the file /etc/apt/sources.list. You'll need to do this as root with sudo:
Next run the following:
deb http://download.virtualbox.org/virtualbox/debian quantal contrib
The second line installs the gcc compiler and associated files and gets the kernel header files that correspond with your current kernel version. (Run the command "uname -r" to see how that works.) The next line installs the Oracle public key as described in the link above. The last two lines remove any existing VB installation and replaces it with a new copy of version 4.2.
sudo apt-get update
sudo apt-get install build-essential linux-headers-$(uname -r)
wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | sudo apt-key add -
sudo apt-get purge virtualbox-*
sudo apt-get install virtualbox-4.2
I've never had a problem with VB when installed from the Oracle repository. You get the nice added feature that the OS will manage any updates for VirtualBox the same way it manages updates for all the other software on your system.