error creating fat client

[Valerio Pachera]

Hi, I'm following this guide:
https://help.ubuntu.com/community/UbuntuLTSP/FatClients

The build proccess stops with the following mesage:
---
Nota, viene selezionato "nfs-common" al posto di "nfs-client"
E: Unable to locate package language-support-writing-it
umount: /opt/ltsp/i386/proc: device is busy.
        (In some cases useful info about processes that use
         the device is found by lsof(8) or fuser(1))
---

I check it:
---
root at extensys-ProLiant-ML310-G2:/opt/ltsp# lsof /opt/ltsp/i386/proc
COMMAND    PID     USER   FD   TYPE DEVICE SIZE/OFF       NODE NAME
rsyslogd   539   syslog    4r   REG    0,3        0 4026532033 /proc/kmsg
lsof       959     root    3r   DIR    0,3        0          1 /proc
lsof       959     root    6r   DIR    0,3        0      78797 /proc/959/fd
acpid     1024     root    4r   REG    0,3        0 4026531979 /proc/acpi/event
Xorg      1059     root    8w   REG    0,3        0 4026531958 /proc/mtrr
Xorg      1059     root   13w   REG    0,3        0 4026531958 /proc/mtrr
udisks-da 1370     root   10r   REG    0,3        0 4026531971 /proc/mdstat
udisks-da 1370     root   12r   REG    0,3        0       9469
/proc/1370/mountinfo
ksysguard 1572 extensys    3r   DIR    0,3        0          1 /proc
rtkit-dae 1687    rtkit  cwd    DIR    0,3        0          1 /proc
rtkit-dae 1687    rtkit  rtd    DIR    0,3        0          1 /proc
---

What do you think about it?