ptweens: 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/ptweens - from package: python-pyramid

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

On Debian possible default full paths are:

/usr/bin/ptweens - from package: python-pyramid

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

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