plastex: 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 Debian possible default full paths are:

/usr/bin/plastex - from package: python-plastex

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

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