MonoDevelop.Core.dll: 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/MonoDevelop.Core.dll - from package: monodevelop

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

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