Hi Adam,
As you already figured out, the trouble was caused by gnupod
trying to find the devices serial number (aka fwid).
The problem is that gnupod used a rather crude way to look for
the device in /sys/block and ubuntu has recently made some big
changes there.
The problem you describe has been reported before:
http://lists.gnu.org/archive/html/bug-gnupod/2009-04/msg00003.html
It would be great if you could check out the current CVS version
of gnupod to see if it works any better:
................
sudo su -
apt-get remove gnupod-tools
apt-get -y install cvs
apt-get -y install autoconf
cvs -z3 -d:pserver:address@hidden:/sources/gnupod co gnupod
cd gnupod
autoconf
./configure
make intall