pwconv: 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/sbin/pwconv - from package: shadow-utils

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

On Debian possible default full paths are:

/usr/sbin/pwconv - from package: passwd

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

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