mllatex: 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/mllatex - from package: texlive-latex

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

On Debian possible default full paths are:

/usr/bin/mllatex - from package: texlive-formats-extra

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

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