monodis: 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/monodis - from package: mono-devel

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

On Debian possible default full paths are:

/usr/bin/monodis - from package: mono-utils

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

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