The package from your repository did not help :(

System: Ubuntu 10.04 LTS

$ sudo lxc-start -n lxc_web -f config -l DEBUG -o $(tty)
      lxc-start 1272588706.041 INFO     lxc_conf - tty's configured
      lxc-start 1272588706.041 DEBUG    lxc_start - sigchild handler set
      lxc-start 1272588706.041 INFO     lxc_start - 'lxc_web' is initialized
      lxc-start 1272588706.078 DEBUG    lxc_cgroup - using cgroup mounted at '/cgroup'
      lxc-start 1272588706.078 DEBUG    lxc_cgroup - '/cgroup/15060' renamed to '/cgroup/lxc_web'
      lxc-start 1272588706.079 DEBUG    lxc_cgroup - using cgroup mounted at '/cgroup'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.deny' set to 'a'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.allow' set to 'c 1:3 rwm'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.allow' set to 'c 1:5 rwm'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.allow' set to 'c 5:1 rwm'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.allow' set to 'c 5:0 rwm'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.allow' set to 'c 4:0 rwm'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.allow' set to 'c 4:1 rwm'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.allow' set to 'c 1:9 rwm'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.allow' set to 'c 1:8 rwm'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.allow' set to 'c 136:* rwm'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.allow' set to 'c 5:2 rwm'
      lxc-start 1272588706.079 DEBUG    lxc_conf - cgroup 'devices.allow' set to 'c 254:0 rwm'
      lxc-start 1272588706.079 INFO     lxc_conf - cgroup has been setup
      lxc-start 1272588706.079 INFO     lxc_conf - mount points have been setup
      lxc-start 1272588706.079 INFO     lxc_conf - console '/dev/pts/0' mounted to '/virt/lxc/guests/web/rootfs/dev/console'
      lxc-start 1272588706.079 INFO     lxc_conf - 4 tty(s) has been setup
      lxc-start 1272588706.080 DEBUG    lxc_conf - temporary mountpoint for old rootfs is './lxc-oldrootfs-HAwj5l'
      lxc-start 1272588706.080 DEBUG    lxc_conf - pivot_root syscall to '/lxc-oldrootfs-HAwj5l' successful
      lxc-start 1272588706.590 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/dev/pts'
      lxc-start 1272588706.798 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/dev/shm'
      lxc-start 1272588707.214 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/sys/fs/fuse/connections'
      lxc-start 1272588707.422 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/sys/kernel/debug'
      lxc-start 1272588707.630 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/sys/kernel/security'
      lxc-start 1272588707.838 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/proc'
      lxc-start 1272588708.046 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/var/run'
      lxc-start 1272588708.254 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/var/lock'
      lxc-start 1272588708.462 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/lib/init/rw'
      lxc-start 1272588708.670 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/tmp'
      lxc-start 1272588708.878 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/boot'
      lxc-start 1272588709.086 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/var'
      lxc-start 1272588709.294 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/www'
      lxc-start 1272588709.502 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/files'
      lxc-start 1272588709.918 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/cgroup'
      lxc-start 1272588710.126 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/virt/lxc/guests/web/rootfs/dev/console'
      lxc-start 1272588710.350 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/virt/lxc/guests/web/rootfs/dev/tty1'
      lxc-start 1272588710.558 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/virt/lxc/guests/web/rootfs/dev/tty2'
      lxc-start 1272588710.766 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/virt/lxc/guests/web/rootfs/dev/tty3'
      lxc-start 1272588710.974 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/virt/lxc/guests/web/rootfs/dev/tty4'
      lxc-start 1272588711.182 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/dev'
      lxc-start 1272588711.390 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/sys'
      lxc-start 1272588711.598 DEBUG    lxc_conf - umounted '/lxc-oldrootfs-HAwj5l/virt'
      lxc-start 1272588711.806 ERROR    lxc_conf - Device or resource busy - could not unmount old rootfs
lxc-start: Device or resource busy - could not unmount old rootfs
      lxc-start 1272588711.806 ERROR    lxc_conf - failed to pivot_root to '/virt/lxc/guests/web/rootfs' lxc-start: failed to pivot_root to '/virt/lxc/guests/web/rootfs'
      lxc-start 1272588711.806 ERROR    lxc_conf - failed to set rootfs for 'lxc_web' lxc-start: failed to set rootfs for 'lxc_web'
      lxc-start 1272588711.806 ERROR    lxc_start - failed to setup the container lxc-start: failed to setup the container
      lxc-start 1272588711.806 NOTICE   lxc_start - '/sbin/init' started with pid '15060'
      lxc-start 1272588711.806 DEBUG    lxc_utils - closing fd '1'
      lxc-start 1272588711.806 DEBUG    lxc_utils - closing fd '0'
      lxc-start 1272588711.806 DEBUG    lxc_utils - closed all inherited file descriptors
      lxc-start 1272588711.833 DEBUG    lxc_start - child exited
      lxc-start 1272588711.833 INFO     lxc_error - child <15060> ended on error (255)
      lxc-start 1272588711.834 DEBUG    lxc_cgroup - using cgroup mounted at '/cgroup'
      lxc-start 1272588711.882 DEBUG    lxc_cgroup - '/cgroup/lxc_web' unlinked