xmltools: 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/xmltools - from package: texlive-context

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

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