# delete old vitualbox install package
apt-get purge virtualbox

# install & download package
wget --no-check-certificate https://www.virtualbox.org/download/oracle_vbox.asc

apt-key add oracle_vbox.asc

echo "deb http://download.virtualbox.org/virtualbox/debian wheezy contrib" >> /etc/apt/sources.list

apt-get update

apt-get install virtualbox-4.2 dkms

# you might also want the guest additions iso
wget http://download.virtualbox.org/virtualbox/4.2.0/VBoxGuestAdditions_4.2.0.iso

# if things fail, try install kernel header files and redo the process
apt-get install linux-headers-$(uname -r)

# it gave me that error: rc -1912
virtualbox on knoppix error rc 1912

root@Microknoppix:~# /etc/init.d/vboxdrv setup
[ ok ] Stopping VirtualBox kernel modules:.
[ ok ] Uninstalling old VirtualBox DKMS kernel modules:.
[ ok ] Trying to register the VirtualBox kernel modules using DKMS:.
[ ok ] Starting VirtualBox kernel modules:

 virtualbox on knoppix error rc 1912 hewego


# PROBLEM: You will have to re-setup the virtualbox kernel modules on every startup...
vim /etc/rc.local

# rc.local
# Start local services after hardware detection


for i in $SERVICES; do
 [ -x /etc/init.d/"$i" ] && /etc/init.d/"$i" start >/dev/null 2>&1

echo "starting ssh deamon"
/etc/init.d/ssh start

echo "reinstall virtualbox kernel modules"
/etc/init.d/vboxdrv setup

exit 0

more instructions: https://www.virtualbox.org/wiki/Linux_Downloads