It has some case of the cause; first, there are insufficient conditions to start driver such as some libraries and hardware requirements… Second, Virtualbox configuration had been broken. In the second case, you need to reinstall Virtualbox.
If you installed virtualbox from the oracle repo then it is up to the user to identify and install any missing dependencies. If you installed it from the rpmfusion repo then all needed dependencies to build the modules should have been handled for you.
The answer to the question from @augenauf in post # 2 would tell us where the problem lies.