Kernel module does not load anymore (Windows Host)

[Heliosmaster]

After upgrading from VirtualBox 4.1.2 to 4.1.4 yesterday, it stopped working at all.

Every time I try to run my Ubuntu host it says that it cannot find the Kernel Module, and return this error:

The virtual machine 'buntu' has terminated unexpectedly during startup.

Codice 'uscita (exit code): E_FAIL (0x80004005)
Componente (component): Machine
Interfaccia (interface): IMachine {5eaa9319-62fc-4b0a-843c-0cb1940f8a91}

(There is no VBox.log file I can attach)

I tried reverting back to 4.1.2 and back to 4.1.4, but it yields the same result. Furthermore, I tried to be very careful about permissions and run everything as an administrator, but it didn't help at all.