I had a similar issue. My guess is you installed from the repo.

There apparently is an issue with the package in the repo

Remove/unistall virtual box.

And download the package directly from the virtual box site.

That worked for me.
On Mar 24, 2015 9:05 AM, "Stephane C. Garcia" <stef@scgarcia.com> wrote:

> Hello All,
>
> I have a problem with Virtualbox....I'm on Fedora 21 and I have installed
> Virtualbox 4.3.26. I have a very common error message  (as far as I see on
> google) Kernel driver not installed (rc=-1908)
> I tried to install DKMS and reinstall the kernel module on
> /etc/init.d/vboxdrv setup but it still failed.
>
> Anyone can help me ?
>
> Thanks in advance
>
> SG
>
> "Si vis pacem para bellum" Publius Flavius Vegetius Renatus
>
> "I might not agree with what you say, but I will fight to death for your
> right to say it" Voltaire (1694 - 1778)
>
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