Qube2 with release-5 hangs, wapbl problem?

I have a Qube2 which I was running release-5 on before, but I recently
used the recovery CD to reinstall onto a new disk. The disk used to be
a regular 60 gig IDE, now it is a 30 gig laptop drive so I can unplug
the fan and use less power.

I wasn't having this problem before I used the restore CD. I noticed
that the default filesystem options include log now in the fstab,
which is why I susbect wapbl. I wasn't using the log option when I
installed release-5 manually before, because I never changed the fstab
or re-formatted the filesystem so I could use it. There have been no
errors logged to /var/log/messages about the new disk at all.

The system becomes generally unresponsive. I can't issue commands. My
VNC desktop is still visible over the network, I can type in a
terminal but as soon as I execute a command that terminal is hung. I
can't start a new one to issue more commands.

I have a serial console, but I can't log in with it once the system is hung.

I'm not hugely interested in debugging it at this point, but I can
probably do it in the next few weeks or so. What should I do? Maybe
set it to panic when I connect via the serial console or something?

My next step is to see if it's safe to remove the log option from the
fstab and reboot. Then I'll see if it hangs again. If not, I think
wapbl is probably a likely candidate. The hang isn't that easy to
generate, but it happens about once a day or so.

Thanks.

Andy