To make this even weirder...
I was just able to run a complete backup using SD. The only item of note that I can come up with is that after the crash prior to this the icon for the firewire drive changed from a yellow disk with the firewire icon to a generic white removeable disk icon.
One other minor thing (that actually has something to do with SD) is that after the backup complete and I hit the OK button, SD went back to it's main window and crashed.
Here is the
log.