functions.sh: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/share/dotlrn/packages/acs-lang/bin/functions.sh - from package: dotlrn
/usr/share/openacs/packages/acs-lang/bin/functions.sh - from package: openacs

You may install the required package with command apt-get install {package}

Error in other languages:
functions.sh: bevel nie gevind nie
functions.sh: comandă negăsită
functions.sh: comando não encontrado
functions.sh: commande introuvable
functions.sh: command not found
functions.sh: käsku ei ole
functions.sh: không tìm thấy lệnh
functions.sh: komanda nerasta
functions.sh: Kommando nicht gefunden.
functions.sh: kommandot finns inte
functions.sh: komut yok
functions.sh: nie znaleziono polecenia
functions.sh: níor aimsíodh an t-ordú
functions.sh: no se encontró la orden
functions.sh: no s'ha trobat l'ordre
functions.sh: opdracht niet gevonden
functions.sh: parancs nem található
functions.sh: perintah tidak ditemukan
functions.sh: príkaz nenájdený
functions.sh: příkaz nenalezen
functions.sh: команда не найдена
functions.sh: командата не е открита
functions.sh: 命令找不到
functions.sh: コマンドが見つかりません