Running VirtualBox on Kali seems a little odd to me, especially when you can't interpret an error message that spells out the solution to you, however, I think the following command (as root) ought to install the required package:
Code:
apt-get install linux-headers-$(uname -r)
Quite how you will proceed from there and whether VirtualBox is of much use on a distribution aimed at Linux experts to carry out penetration testing only I cannot say.
