I installed a VirtualBox and then installed a Ubuntu 12.10 Server Base OS in it. I have installed all kinds of php packages and other packages in it. My friends recommended me t
The packaging guide in "Getting Started" you are referring to assumes you have started from a vagrant base box and initialized it with vagrant up, which you have not. This allows you to package any customizations you have made to a vagrant base box.
If you start from scratch or from a "plain" VirtualBox
VM, as you do, you need to create a vagrant base box. You should be fine following the guide, which is based on Ubuntu.