In plain English this happens after you upgrade VBOX and it rebuilds kernel modules based on a newer kernel than you are running (eg. you upgraded your kernel but haven't booted into it).
It is too bad there is not a standard work around that would allow it to realize this and keep old kernel modules and use them if it detects your current kernel is older than the most recently build modules.
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RTR3InitEx failed with rc=-1912 (rc=-1912)
The VirtualBox kernel modules do not match this version of VirtualBox. The installation of VirtualBox was apparently not successful. Executing
'/etc/init.d/vboxdrv setup'
may correct this. Make sure that you do not mix the OSE version and the PUEL version of VirtualBox.
Result Code:
NS_ERROR_FAILURE (0x80004005)
Component:
Machine
Interface:
IMachine {480cf695-2d8d-4256-9c7c-cce4184fa048}
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