monodocs2html: 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/monodocs2html - from package: monodoc

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

On Debian possible default full paths are:

/usr/bin/monodocs2html - from package: monodoc-base

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

Error in other languages:
monodocs2html: bevel nie gevind nie
monodocs2html: comandă negăsită
monodocs2html: comando não encontrado
monodocs2html: commande introuvable
monodocs2html: command not found
monodocs2html: käsku ei ole
monodocs2html: không tìm thấy lệnh
monodocs2html: komanda nerasta
monodocs2html: Kommando nicht gefunden.
monodocs2html: kommandot finns inte
monodocs2html: komut yok
monodocs2html: nie znaleziono polecenia
monodocs2html: níor aimsíodh an t-ordú
monodocs2html: no se encontró la orden
monodocs2html: no s'ha trobat l'ordre
monodocs2html: opdracht niet gevonden
monodocs2html: parancs nem található
monodocs2html: perintah tidak ditemukan
monodocs2html: príkaz nenájdený
monodocs2html: příkaz nenalezen
monodocs2html: команда не найдена
monodocs2html: командата не е открита
monodocs2html: 命令找不到
monodocs2html: コマンドが見つかりません