pygettext3: 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/pygettext3 - from package: python3

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

Error in other languages:
pygettext3: bevel nie gevind nie
pygettext3: comandă negăsită
pygettext3: comando não encontrado
pygettext3: commande introuvable
pygettext3: command not found
pygettext3: käsku ei ole
pygettext3: không tìm thấy lệnh
pygettext3: komanda nerasta
pygettext3: Kommando nicht gefunden.
pygettext3: kommandot finns inte
pygettext3: komut yok
pygettext3: nie znaleziono polecenia
pygettext3: níor aimsíodh an t-ordú
pygettext3: no se encontró la orden
pygettext3: no s'ha trobat l'ordre
pygettext3: opdracht niet gevonden
pygettext3: parancs nem található
pygettext3: perintah tidak ditemukan
pygettext3: príkaz nenájdený
pygettext3: příkaz nenalezen
pygettext3: команда не найдена
pygettext3: командата не е открита
pygettext3: 命令找不到
pygettext3: コマンドが見つかりません