latexmlc: 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/latexmlc - from package: latexml

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

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