Unknown error creating VM (verr_hostif_init_failed) appears in virtualbox ose in Ubuntu)

My Nic is shared by the host interface. It may have changed the Host Name of the machine in a few days, so this error occurs.
Google, the solution is as follows:
See: http://www.giannistsakiris.com/index.php/2007/11/25/unknown-error-creating-vm-verr_hostif_init_failed/

Unknown error creating VM (verr_hostif_init_failed ).
Vbox status code:-3100 (verr_hostif_init_failed ).

While trying to start your virtualbox on Ubuntu, then it's probably
Because the user by which virtualbox is running does not have
Read/write permissions on/Dev/NET/TUN. To solve the problem run this commands:

sudo chgrp vboxusers /dev/net/tun
sudo chmod 660 /dev/net/tun

Then add the user that is going to use virtualbox toVboxusersGroup. Run the following command:

sudo gedit /etc/group

FindVboxusersGROUP:

...
mysql:x:121:
vboxusers:x:1001:
postfix:x:122:
...

And add all the users that will use virtualbox into it:

...
mysql:x:121:
vboxusers:x:1001:giannis
postfix:x:122:
...

Save the file and exitGedit. You shoshould not get this error any more.