Since few days I cannot boot with RHEL4
I get these messages :

ext3-fs error (device dm-0): ext3_check_descriptors: Block bitmap for group 128 not in group (block 2151710720)
ext3-fs : group descriptor corrupted !

mount : error 22 mounting ext3
mount : error 2 mounting none
switchroot : mountfailed : 22
umount /initrd/dev failed : 2
Kernel panic - not syncing : attempted to kill init !

Else in rescue mode, when it searchs for an existing installation:
"error when mounting the filesystem on hdb1 : no peripherical or address" (same message with hdd1 device)
Then : "You have no linux partition linux, press enter to get a shell".

Thanks a lot to tell me how to fix that.

Well, it sounds like your hard drive has problems....replace it, and restore from backup.

I had a similar problem with mandriva 2008.
I tried fsck but it failed again.
So I have made up my mind to reinstall it (fortunately I saved my docs just before), it works but now I am stuck on wifi config.
Fortunately I have other Linux distros!