Well, this is what i do:
1.Open m VirtualBox and then choose the ubuntu VM
2.It is loading from the official .iso file, from ubuntu servers
3.Start loading, as a live cd would.
4.The orange bar goes >> and << and >>..... then it starts filling in, like >>>>
5.When it fills, it shows a Loading... please wait message, the shows up this screen:
Ok, i managed to printscreen the message that appears befor that screen.
Here it goes: