EXT2-fs error

[Robin Gerard <robin.jag@free.fr>]

Hello,
after my box crashed and when I booted the machine agai I got the message:

.......
ext3 No journal on filesystem on ide0(3, 4)
mount: wrong fs type, bad option, bad superblock on /dev2/root2, or
too many mounted file system.
........
however fsck said that '/dev/hda4' is clean and I can use linux almost 
as usual; almost, that unfortunately, if I run 'updatedb' (as root) I get:

EXT2-fs errror  device ide0(3, 4): ext2_check_page: size of directory
#8418985 is not a multiple of chunk size
Remounting filesystem read-only
rm: cannot remove '/usrcache/locate/locatedb': Read-only filesystem
mv: overwrite ' /usrcache/locate/locatedb', owerriding mode 0644 ?

Is it possible to repair my filesystem ?
And how can'I do it ?
My kernel is 2.4.20-386 (package Debian) 

tia 
-- 
Gerard