Completely fresh from r1 to r2:
Verifying archive integrity... All good.
Uncompressing VirtualBox 4.1.8 Guest Additions for Linux.........
VirtualBox Guest Additions installer
Removing installed version 4.1.8 of VirtualBox Guest Additions...
tar: Record size = 8 blocks
Removing existing VirtualBox DKMS kernel modules ...done.
Removing existing VirtualBox non-DKMS kernel modules ...done.
Building the VirtualBox Guest Additions kernel modules
The headers for the current running kernel were not found. If the following
module compilation fails then this could be the reason.
Building the main Guest Additions module ...fail!
(Look at /var/log/vboxadd-install.log to find out what went wrong)
Doing non-kernel setup of the Guest Additions ...done.
Installing the Window System drivers
Installing X.Org Server 1.7 modules ...done.
Setting up the Window System to use the Guest Additions ...done.
You may need to restart the hal service and the Window System (or just restart
the guest system) to enable the Guest Additions.
Installing graphics libraries and desktop services components ...done.
Press Return to close this window...
root@bt:/# cat /var/log/vboxadd-install.log
Uninstalling modules from DKMS
Attempting to install using DKMS
Creating symlink /var/lib/dkms/vboxguest/4.1.8/source ->
DKMS: add Completed.
Error! Your kernel headers for kernel 3.2.6 cannot be found at
/lib/modules/3.2.6/build or /lib/modules/3.2.6/source.
You can use the --kernelsourcedir option to tell DKMS where it's located, or you could install the linux-headers-3.2.6 package.
Failed to install using DKMS, attempting to install without
/tmp/vbox.0/Makefile.include.header:94: *** Error: unable to find the sources of your current Linux kernel. Specify KERN_DIR=<directory> and run Make again. Stop.
Creating user for the Guest Additions.
Creating udev rule for the Guest Additions kernel module.