debian - Error while installing virtualbox

I am running debian 7 and trying to install virtualbox using:

sudo apt-get install virtualbox

and getting this output:

Selecting previously unselected package virtualbox.
Unpacking virtualbox (from .../virtualbox_4.1.18-dfsg-2+deb7u1_amd64.deb) ...
Selecting previously unselected package virtualbox-dkms.
Unpacking virtualbox-dkms (from .../virtualbox-dkms_4.1.18-dfsg-2+deb7u1_all.deb) ...
Selecting previously unselected package virtualbox-qt.
Unpacking virtualbox-qt (from .../virtualbox-qt_4.1.18-dfsg-2+deb7u1_amd64.deb) ...
Processing triggers for man-db ...
Processing triggers for menu ...
Processing triggers for hicolor-icon-theme ...
Processing triggers for shared-mime-info ...
Processing triggers for desktop-file-utils ...
Setting up libvncserver0:amd64 (0.9.9+dfsg-1) ...
Setting up virtualbox (4.1.18-dfsg-2+deb7u1) ...
insserv: script virtualbox: service vboxdrv already provided!
insserv: exiting now!
update-rc.d: error: insserv rejected the script header
dpkg: error processing virtualbox (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of virtualbox-dkms:
 virtualbox-dkms depends on virtualbox (>= 4.1.18-dfsg-2+deb7u1); however:
  Package virtualbox is not configured yet.

dpkg: error processing virtualbox-dkms (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of virtualbox-qt:
 virtualbox-qt depends on virtualbox (= 4.1.18-dfsg-2+deb7u1); however:
  Package virtualbox is not configured yet.

dpkg: error processing virtualbox-qt (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 virtualbox
 virtualbox-dkms
 virtualbox-qt
E: Sub-process /usr/bin/dpkg returned an error code (1)

can anybody help?