Virtualbox startup error

Problem description:

I received a message similar to the following after a gentoo update. It is related to a kernel module called vboxnetflt

Failed to open/create the internal network 'HostInterfaceNetworking-eth0' (VERR_SUPDRV_COMPONENT_NOT_FOUND). Unknown error creating VM (VERR_SUPDRV_COMPONENT_NOT_FOUND)

Solution:

load the kernel module:

 modprobe vboxnetflt

to load automatically on boot, add the module name to the appropriate line in /etc/conf.d/modules

 example, add module name to the line ...
   modules="vboxnetflt vboxdrv"