elementary_quicklaunch: 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/elementary_quicklaunch - from package: libelementary-bin

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

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