latexmlmath: 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/latexmlmath - from package: latexml

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

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