Actualizando a Lenny me encontré (aunque claro lo mejor hubiera sido leer las release notes cosa que hice después de actualizar la segunda maquina):
glibc (2.5-1) unstable; urgency=low
Starting with version 2.5-1, the glibc requires a 2.6.1 or later
kernel. If you use a 2.4 kernel, please upgrade it *before*
installing glibc.This also means that it is not possible to use LD_ASSUME_KERNEL with a
version lower than 2.6.1. If you have set such a thing in /etc/profile,
~/.bashrc or any other initialization file (something you should have
never done!!!), please remove that *before* installing glibc.Note: This does not apply to the m68k architecture and to non-Linux
kernels.
A hacer pruebas con fakeroot y make-kpkg por que en la linea 2.6.x cambian muchísimas cosas
