mpstools: 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/mpstools - from package: texlive-context

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

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