newslock: 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/newslock - from package: mgetty-sendfax

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

On Debian possible default full paths are:

/usr/bin/newslock - from package: mgetty-fax

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

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