jw: 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/jw - from package: docbook-utils

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

On Debian possible default full paths are:

/usr/bin/jw - from package: docbook-utils

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

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