Forgot to mention, have you installed VirtualBox Extension Pack? if not, then do following steps:
1. Download VB extension pack:
VirtualBox 4.1.18 Extension Pack
2. Install ext pack:
Code:
$ sudo VBoxManage extpack install Oracle_VM_VirtualBox_Extension_Pack-4.1.18-78361.vbox-extpack
3. Recompile the vbox module:
Code:
$ sudo /etc/init.d/vboxdrv setup
4. follow steps in post #2
Note: the latest version of VirtualBox is 4.2.12. i recommend you install the latest version