You might try mounting the filesystem briefly as an ext2. Then, perhaps 
you could (under rh7.3) tune2fs -j the thing to get it back to a 
7.3-vintage ext3. Just a wild guess; no idea whether this has much chance 
of helping (or much chance of not hurting!).

-Jan

On Tue, 8 Jul 2008, Paul Casteels wrote:

> Date: Tue, 08 Jul 2008 06:59:48 -0500
> From: Paul Casteels <[log in to unmask]>
> To: [log in to unmask]
> Cc: Paul Casteels <[log in to unmask]>
> Subject: ext3 filesystem
> 
> One of our machines has to remain at RedHat 7.3 and crashed it's disk.
> With one of SL LiveCD's I was able to restore everything.
> During boot I received a message like
>  fsck.ext3: Filesystem has unsupported features
>  e2fsck: Get a newer version of e2fsck
> and fails to mount.
> It has e2fsprogs-1.27-3 but since it cannot boot I cannot upgrade.
> With debugfs I checked and removed some features but I could not get it g
> oing.
> It appears that something changed in ext3 that makes it not backwards
> compatible. Maybe an SL3 LiveCD could help but that seems not available.
>