uwsgi_v8: 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/uwsgi_v8 - from package: uwsgi-plugin-v8

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

Error in other languages:
uwsgi_v8: bevel nie gevind nie
uwsgi_v8: comandă negăsită
uwsgi_v8: comando não encontrado
uwsgi_v8: commande introuvable
uwsgi_v8: command not found
uwsgi_v8: käsku ei ole
uwsgi_v8: không tìm thấy lệnh
uwsgi_v8: komanda nerasta
uwsgi_v8: Kommando nicht gefunden.
uwsgi_v8: kommandot finns inte
uwsgi_v8: komut yok
uwsgi_v8: nie znaleziono polecenia
uwsgi_v8: níor aimsíodh an t-ordú
uwsgi_v8: no se encontró la orden
uwsgi_v8: no s'ha trobat l'ordre
uwsgi_v8: opdracht niet gevonden
uwsgi_v8: parancs nem található
uwsgi_v8: perintah tidak ditemukan
uwsgi_v8: príkaz nenájdený
uwsgi_v8: příkaz nenalezen
uwsgi_v8: команда не найдена
uwsgi_v8: командата не е открита
uwsgi_v8: 命令找不到
uwsgi_v8: コマンドが見つかりません