altree-convert: 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/altree-convert - from package: altree

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

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