neutron-l3-agent: 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

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/bin/neutron-l3-agent - from package: neutron-common

You may install the required package with command apt-get install {package}
Error in other languages:
neutron-l3-agent: bevel nie gevind nie
neutron-l3-agent: comandă negăsită
neutron-l3-agent: comando não encontrado
neutron-l3-agent: commande introuvable
neutron-l3-agent: command not found
neutron-l3-agent: käsku ei ole
neutron-l3-agent: không tìm thấy lệnh
neutron-l3-agent: komanda nerasta
neutron-l3-agent: Kommando nicht gefunden.
neutron-l3-agent: kommandot finns inte
neutron-l3-agent: komut yok
neutron-l3-agent: nie znaleziono polecenia
neutron-l3-agent: níor aimsíodh an t-ordú
neutron-l3-agent: no se encontró la orden
neutron-l3-agent: no s'ha trobat l'ordre
neutron-l3-agent: opdracht niet gevonden
neutron-l3-agent: parancs nem található
neutron-l3-agent: perintah tidak ditemukan
neutron-l3-agent: príkaz nenájdený
neutron-l3-agent: příkaz nenalezen
neutron-l3-agent: команда не найдена
neutron-l3-agent: командата не е открита
neutron-l3-agent: 命令找不到
neutron-l3-agent: コマンドが見つかりません