caribou-preferences: 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/bin/caribou-preferences - from package: caribou

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

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