fai-setup on "ubuntu 12.04 LTS precise" does not complete

[Hiro Protagonist]

hello

i tried to run fai-setup on "ubuntu 12.04 LTS precise" 
(fai-server:3.4.8ubuntu2). fai-setup terminated with the following error 
message:

(for readability i replaced the packages aptitude wants to install with 
"...")


install_packages: executing chroot /srv/fai/nfsroot/live/filesystem.dir 
aptitude -R -y -o Dpkg::Options::="--force-confdef" -o 
Dpkg::Options::="--force-confold" install nfs-common ... linux-image-server

chroot: failed to run command `aptitude': No such file or directory

ERROR: 32512 32512

ERROR: chroot /srv/fai/nfsroot/live/filesystem.dir aptitude -R -y -o 
Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" 
install nfs-common ... linux-image-server return code 127



it seems that aptitude is not installed with the base system. am i doing 
something wrong? or can i fix this?


thanks in avance!