VirtualBox 3.1 Error in Oracle

My problem is related to Oracle. I have an Oracle Virtual Memory in my VirtualBox 3.1 and I had it for quite some time already. I think it sends a dialog box everyday asking me to install some updates for the software but I did not try to install anything. Now I was tempted to install because I see the same dialog box every time I run Oracle. I guess I have installed the latest updates and version of it. The installation was very smooth and it finished without any error. But when I started running it for the first time after its complete installation, I got this error message saying: Unknown error creating VM (VERR_ NOT_FOUND). I was disappointed to see that. I have attached the error message below:

VirtualBox – Error

Failed to open a session for the virtual machine racnode1

Implementation of the USB 2.0 controller not found!

Because the USB 2.0 controller state is part of the saved VM state, the VM cannot be started. To fix the problem, either install the 'Oracle VM VirtualBox Extension Pack' or disable USB 2.0 support in the VM settings (VERR_NOT_FOUND).

Unknown error creating VM (VERR_NOT_FOUND).