zfs discuss - Aug 2009 - Behind the scenes of ''invalid vdev configuration''

I am dealing with a zpool that''s refusing to import, and reporting  
invalid vdev configuration.

How can I learn more about what exactly this means? Can I isolate  
which disk(s) are missing or corrupted/failing?

zpool import provides some information, but not enough. Confusingly,  
it lists all disks as ''online'' as well, even if they are
physically
not present.

Suggestions anybody?

-Galen