How to troubleshoot why VirtualBox kernel module freezes the system?

[Yuri]

Alexey Shuvaev wrote:
> Trivial suggestion: have you rebuilt virtualbox with new kernel sources?
> What are the versions of FreeBSD / virtualbox?
>   

Of course I rebuilt VirtualBox after kernel update.
FreeBSD xxx.xxx.xxx 8.0-STABLE FreeBSD 8.0-STABLE #0: Mon Apr 26 
19:32:12 PDT 2010     yuri at xxx.xxx.xxx:/usr/obj/usr/src/sys/GENERIC  i386
virtualbox-ose-3.1.6_3, virtualbox-ose-kmod-3.1.6

> As a record it is running fine here:
> ~> uname -a
> FreeBSD wep4035 9.0-CURRENT FreeBSD 9.0-CURRENT #0 r206758: Sat Apr 17 17:37:46 CEST 2010     root at wep4035:/usr/obj/usr/src/sys/GENERIC  amd64
> ~> ls /var/db/pkg/virtualbox-ose-
> virtualbox-ose-3.1.6_2/    virtualbox-ose-kmod-3.1.6

Obviously there are two major differences: 9.0-CURRENT and amd64. I am 
not sure which one matters for the problem.

Yuri