mdmonitor.exe: 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/lib/monodevelop/bin/mdmonitor.exe - from package: monodevelop

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

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