gunicorn_django: 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 CentOS possible default full paths are:

/usr/bin/gunicorn_django - from package: python-gunicorn

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/gunicorn_django - from package: gunicorn

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

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