cairo-dock: command not found

Have You tried accessing the binary with the full path?

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/cairo-dock - from package: cairo-dock-core

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