qtdump: 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/qtdump - from package: quicktime-utils

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

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