MonoDevelop.exe.addins: command not found

Have You tried accessing the binary with the full path?

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.exe.addins - from package: monodevelop

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