uwsgi_php: 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_php - from package: uwsgi-plugin-php

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

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