I have the same issue and I don't see any subdirectory belonging to older versions of VB in /var/lib/dkms/vboxhost
/var/lib/dkms/vboxhost$ ls -la total 12 drwxr-xr-x 3 root root 4096 May 23 20:07 . drwxr-xr-x 7 root root 4096 May 23 20:06 .. drwxr-xr-x 4 root root 4096 May 23 20:07 4.1.14 lrwxrwxrwx 1 root root 28 May 23 20:07 kernel-3.2.0-24-generic-i686 -> 4.1.14/3.2.0-24-generic/i686
So VirtualBox developer say it's a bug in Ubuntu, and Ubuntu developers say it's a bug in VirtualBox..........
I have the same issue and I don't see any subdirectory belonging to older versions of VB in /var/lib/ dkms/vboxhost
/var/lib/ dkms/vboxhost$ ls -la 3.2.0-24- generic- i686 -> 4.1.14/ 3.2.0-24- generic/ i686
total 12
drwxr-xr-x 3 root root 4096 May 23 20:07 .
drwxr-xr-x 7 root root 4096 May 23 20:06 ..
drwxr-xr-x 4 root root 4096 May 23 20:07 4.1.14
lrwxrwxrwx 1 root root 28 May 23 20:07 kernel-
So VirtualBox developer say it's a bug in Ubuntu, and Ubuntu developers say it's a bug in VirtualBox. ....... ..