Using a native FreeBSD kernel on Debian GNU/kFreeBSD brings trouble because of kern.module_path not being set early enough (it is needed when /etc/init.d/freebsd-utils mounts /proc). Here is a patch.
What do you mean by native FreeBSD kernel ? The stock FreeBSD kernel without GNU/kFreeBSD patches ? At least 007_clone_signals.diff is essential for threaded programs. Petr