OK, software before hardware is good... What version are you using?

Don't recall what stage 2 implies and can't locate the description I know is out there somewhere - maybe The Guardian of the FAQ :-), Tony, can point it out?

group descriptors corrupted doesn't sound good, but I'm no guru.
Try fsck'ing the disk - instructions here.

It could be a bad drive cable causing this - if the fsck (and possibly a new application of the system through a .upgrade file - I think you'd at least want to get to latest stable release, 1.03, compared to the 1.02 it came with shipped, anyway) doesn't help you'll want to contact support at [email protected].
Upgrade PC software first, empeg last. If the filesystem on the disk is really messed up you might also try applying the disk-builder .upgrade file for a fresh start.

/Michael