reset_pw.pyc: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/lib/mailman/bin/reset_pw.pyc - from package: mailman

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