virtualbox.org

Hi everyone, i have some problems with any version of VirtualBox.
When i try to start a VM this error is displayed on my screen:
And this few seconds later:
I think it was happening since i installed genymotion with its version of VirtualBox. I unistalled genymotion and i have reinstalled VirtualBox, but nothing, always the same error.
Someone can help me?
Thanks.

No one can help me?

There's a link I found searching for "timed out after waiting for child request":

viewtopic.php?f=6&t=75400

If that doesn't help, please provide: Minimal information needed to be able to help