dpkg/debconf problem installing custom .deb package

Hello,

  I have created a custom kernel .deb package for implementing "the alternative firewire stack (EXPERIMENTAL)" because latest kernel in hardy alpha 4 does not include this feature and everything goes right and .deb kernel-headers installs but trying to install the image using dpkg, I have this error, and it never happened to me with other ubuntu versions:

root@modr:/usr/src# dpkg -i linux-image-2.6.24_2.6.24-10.00.Custom_i386.deb
Seleccionando el paquete linux-image-2.6.24 previamente no seleccionado.
(Leyendo la base de datos ...
122460 ficheros y directorios instalados actualmente.)
Desempaquetando linux-image-2.6.24 (de linux-image-2.6.24_2.6.24-10.00.Custom_i386.deb) ...
Done.
Configurando linux-image-2.6.24 (2.6.24-10.00.Custom) ...
Running depmod.
Finding valid ramdisk creators.
Using mkinitramfs-kpkg to build the ramdisk.
Running postinst hook script update-grub.
Searching for GRUB installation directory ... found: /boot/grub
Searching for default file ... found: /boot/grub/default
Testing for an existing GRUB menu.lst file ... found: /boot/grub/menu.lst
Searching for splash image ... none found, skipping ...
Found kernel: /vmlinuz
Found kernel: /vmlinuz.old
Found kernel: /vmlinuz-2.6.24-5-generic
Found kernel: /vmlinuz-2.6.24
Found kernel: /memtest86+.bin
debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Recurso temporalmente no disponible
User postinst hook script [update-grub] exited with value 1
dpkg: error al procesar linux-image-2.6.24 (--install):
 el subproceso post-installation script devolvi�� el c��digo de salida de error 1 <---PLEASE FIX THIS SYMBOLS ALSO "ó in spanish"
Se encontraron errores al procesar:
 linux-image-2.6.24
root@modr:/usr/src#

  I have tried to kill process blocking config.dat using "lsof" but anyone found.
Thanks,
Alberto :)