Kernel offset disabled [ Virtual Box ]

I am trying to install UBUNTU LINUX in my virtual box. Everything went fine as i followed my lecture but i got stuck at the last place i.e it is showing kernel offset disabled.
I am having no idea on how to manage this. Please let me know asap
I have attached the screenshot below about the problem.

Well, I found the solution on my own since no one answered.
For people who might get stuck on this step i request you to increase your RAM size above 3GB. First you must delete the existing UBUNTU and then again create new and set the RAM mentioned.

please check this video on youtube