Fatal trap 12 on ZFS in 8.0-RC1

Hello,

I'm experimenting with ZFS on 8-0-RC1 (amd64) in a VMWare virtual
machine w/2GB RAM.  In installed ZFS on GPT root using the excellent
instructions at http://wiki.freebsd.org/RootOnZFS/GPTZFSBoot/RAIDZ1.

All was well until I tried some benchmarking with
benchmarks/unixbench.  I kept getting kmem_map too small panics on the
filesystem tests so starting playing with vm.kmem_size.

I finally got unixbench through the first 6 Filesystem Throughput
tests with:
vm.kmem_size="1296M"
vm.kmem_size_max="1296M"
vfs.zfs.arc_max="128M"
vfs.zfs.vdev.cache.size="24M" (i think)

Unfortunately, ZFS paniced with:
Fatal trap 12: page fault while in kernel mode. Now, when I attempt to
restart the VM, as soon as the "boot menu" is gone, I immediately get
the same Fatal trap 12 panics again and cannot get past this point.

I've got the 8.0-RC1 DVD and can run Fixit, but have no idea how to
repair this broken ZFS installation.  Suggestions welcome.

-- 
Regards,
Doug