mdeltree: 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 CentOS possible default full paths are:

/usr/bin/mdeltree - from package: mtools

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/mdeltree - from package: mtools

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

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