Attempting to install using DKMS
  removing old DKMS module vboxdrv version  2.2.4

-------- Uninstall Beginning --------
Module:  vboxdrv
Version: 2.2.4
Kernel:  2.6.31-8-generic (i686)
-------------------------------------

Status: Before uninstall, this module version was ACTIVE on this kernel.

vboxdrv.ko:
 - Uninstallation
   - Deleting from: /lib/modules/2.6.31-8-generic/updates/dkms/
 - Original module
   - No original module was found for this module on this kernel.
   - Use the dkms install command to reinstall any previous module version.

depmod........

DKMS: uninstall Completed.

------------------------------
Deleting module version: 2.2.4
completely from the DKMS tree.
------------------------------
Done.

Creating symlink /var/lib/dkms/vboxdrv/2.2.4/source ->
                 /usr/src/vboxdrv-2.2.4

DKMS: add Completed.

Error! Your kernel source for kernel 2.6.28-15-generic cannot be found at
/lib/modules/2.6.28-15-generic/build or /lib/modules/2.6.28-15-generic/source.
You can use the --kernelsourcedir option to tell DKMS where it's located.
Failed to install using DKMS, attempting to install without
Makefile:145: *** Error: unable to find the sources of your current Linux kernel. Specify KERN_DIR=<directory> and run Make again.  Stop.