twistd: 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/twistd - from package: python-twisted-core

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

On Debian possible default full paths are:

/usr/bin/twistd - from package: python-twisted-core

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

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