How To fix "VirtualBox is not currently allowed to access USB devices" on ubuntu 12.04

I have just found a problem when I using virtual box 4.1 that I installed on ubuntu 12.04. the problem is the usb serial cann't be accessed by virtual box. As the message I get,

Failed to access the USB subsystem.

VirtualBox is not currently allowed to access USB devices. You can change this by adding your user to the 'vboxusers' group. Please see the user manual for a more detailed explanation.

After I search in google and click some website, finnaly I get the problem solving. The way so that your problem solved is you should make virtualbox user to the your group user. The command is usermod -a -G vboxusers "username". For the example, my user named winata. So the command is sudo usermod -a -G vboxusers "username", . Then you logout after logout back to log in.

now your problem solved, and the error message has disappeared.

 

reference : http://ubuntuforums.org/archive/index.php/t-1889090.html