mutool: 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/mutool - from package: mupdf-tools

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

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