python2.6-prody: 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/python2.6-prody - from package: python2-ProDy

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

Error in other languages:
python2.6-prody: bevel nie gevind nie
python2.6-prody: comandă negăsită
python2.6-prody: comando não encontrado
python2.6-prody: commande introuvable
python2.6-prody: command not found
python2.6-prody: käsku ei ole
python2.6-prody: không tìm thấy lệnh
python2.6-prody: komanda nerasta
python2.6-prody: Kommando nicht gefunden.
python2.6-prody: kommandot finns inte
python2.6-prody: komut yok
python2.6-prody: nie znaleziono polecenia
python2.6-prody: níor aimsíodh an t-ordú
python2.6-prody: no se encontró la orden
python2.6-prody: no s'ha trobat l'ordre
python2.6-prody: opdracht niet gevonden
python2.6-prody: parancs nem található
python2.6-prody: perintah tidak ditemukan
python2.6-prody: príkaz nenájdený
python2.6-prody: příkaz nenalezen
python2.6-prody: команда не найдена
python2.6-prody: командата не е открита
python2.6-prody: 命令找不到
python2.6-prody: コマンドが見つかりません