VirtualBox for Ubuntu 16

Ok. I'm trying to get VirtualBox going on my machine. I have a Lenovo x131e Chromebook running Ubuntu 16.04 through Crouton. The kernel version is 3.8.11. I'm trying to run VirtualBox. I installed it from the Ubuntu repository, along with virtualbox-dkms. But when I run VirtualBox, it says this:

Please install the virtualbox-dkms package and the appropriate headers, most likely linux-headers-3.8.11.

I tried to install headers for 3.8.11, but:

E: Unable to locate package linux-headers-3.8.11
E: Couldn't find any package by glob 'linux-headers-3.8.11'
E: Couldn't find any package by regex 'linux-headers-3.8.11'

I was able to install linux-headers-generic, based on someone else's advice, and I did the reconfigure thing for VirtualBox and

virtualbox-dkms, but I still get the aforementioned error:

Please install the virtualbox-dkms package and the appropriate headers, most likely linux-headers-3.8.11.

So what do I do? I want this thing to work. And hell, I'll take VirtualBox, I'll take VMWare, I'll take anything, just so I can run virtual machines. Someone please help me.