It looks like a broken install script. You should only be concerned if,
VirtualBox is not working or you cannot install or upgrade until it is
fixed. I am assuming yes to both, so you should fix it.

I would first open a terminal and type(or cut and paste):sudo dpkg
--configure -a
If that fails try: sudo apt-get install -f

Then I would remove VirtualBox and re-install it. You may have to clean
your cache first if you have a broken package because it will just
re-install from the cache without downloading a fresh copy. Removing
VirtualBox will not delete your VMS, but you may have to re-link then once
VB is re-installed.

sudo apt-get remove virtualbox
sudo apt-get clean
sudo apt-get install virtualbox

(note: if you are using the non-free one go to the VirtualBox website
instead of using the ose version in the repositories. It is better anyway as
it gives you usb support.)