How upgrade kernel installed by debian-dell-2.4.31.iso

[Arnau]

Hi all,

   I've got two powerdege 2850 with 5 disks to configure:) I've
installed the iso debian-dell-2.4.31.iso downloaded from
http://staff.osuosl.org/~kveton/debian/debian-dell-2.4.31.iso. The
installation has been very smooth, the problems arised when I tried to
upgrade to the latest kernel available in backports. I have tried
different combinations and I always get "I have been able to find a
suitable tool for generating initrd images", Anybody know how to solve this?

Thank you very much
-- 
Arnau