ZFS Kernel Panics with 32 and 64 bit versions of 8.3 and 9.0

[Michael Richards]

Originally I had an 8.1 server setup on a 32bit kernel. The OS is on a
UFS filesystem and (it's a mail server) the business part of the
operation is on ZFS.

One day it crashed with an odd kernel panic. I assumed it was a memory
issue so I had more RAM installed. I tried to get a PAE kernel working
to use this extra ram but it was crashing every few hours.

Suspecting a hardware issue all the hardware was replaced.

I had some difficulty trying to figure out how to mount my old ZFS
partition but eventually did so.

zpool import shows this:
pool: email
    id: 10433152746165646153
 state: ONLINE
status: The pool was last accessed by another system.
action: The pool can be imported using its name or numeric identifier and
        the '-f' flag.
   see: http://www.sun.com/msg/ZFS-8000-EY
config:

        email       ONLINE
          ada1s1g   ONLINE

zpool import -f -R /altroot 10433152746165646153 olddata
panics the kernel. Similar panic as seen in all the other kernel versions.

http://forums.freebsd.org/attachment.php?attachmentid=1545&stc=1&d=1336261809

Shows a typical kernel panic.

http://forums.freebsd.org/showthread.php?t=31820

Gives a bit more info about things I've tried. Whatever it is seems to
affect a wide variety of kernels.

Any ideas?