Hi Seb!
I'm guessing from some of your previous posts that you're running the VM on Windows..? If so, could it simply be a matter that Windows has taken over the Crazyradio and did not release it to the VM? I'm not entirely sure how this works on Windows (I'm a Mac user) but I know on Mac it can cause a problem with VMs getting access to devices.
I also found
this thread (a little old though) on the VirtualBox forum. It has some suggestions - you might have already seen it.
Probably not much help, I know.