Right, Ubuntu is for some reason missing a link "libGL.so" in their /usr/bin, so you have to create it yourself. Assuming your actual OpenGL is "libGL.so.1.2" (it might not be, hence the need for the check mentioned in my previous post), you need to do this:
sudo ln -s /usr/lib/libGL.so.1.2 /usr/lib/libGL.so
But first check that you have "libGL.so.1.2" in /usr/lib; you might have "libGL.so.1" or something else instead, depending on the video drivers.
Right, and then as written above you do
sudo ln -s /usr/lib/libGL.so.1.2 /usr/lib/libGL.so
and you should be able to start VNL.