zfs error ?

[n ramrani]

Hi,

 I have FreeBSD 7.0-RELEASE-p4.
I do this:
>portsnap fetch
>portsnap update
>/usr/sbin/freebsd-update fetch
>/usr/sbin/freebsd-update install
After a reboot of my server
I have:
"kmem-suballoc : bad status return of 3
panic: kmeme_suballoc
cpuid=0 "*

On the prompt,i try
> show vm.kmem_size
1024
>show vm.kmem_size_max
1024
I try to change to
> set vm.kmem_size="1536M"
> set vm.kmem_size_max="1536M"
 show  value is ok ,but when i try to do
>boot -s
I have the same  message *
how can i take back the hand on system ?
> thanks.