mtxtools: 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/mtxtools - from package: texlive-context

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

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