neutron-netns-cleanup: 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/bin/neutron-netns-cleanup - from package: neutron-common

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

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