kld vboxguest.ko depends on kernel - not available or version mismatch linker_load_file unsupported file type
Over to maintainers.
got same problem on FreeBSD 11.0 amd64 Name : virtualbox-ose-additions Version : 4.3.30 Installed on : Wed Jul 15 21:15:54 CEST 2015
Most likely your kernel and source files do not match.
this problem occurred on a new install of freebsd 9.3 i386 a subsequent upgrade to 9-stable fixed it
Could be closed, is fixed.