gnuhtml2latex: 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/gnuhtml2latex - from package: gnuhtml2latex

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

Error in other languages:
gnuhtml2latex: bevel nie gevind nie
gnuhtml2latex: comandă negăsită
gnuhtml2latex: comando não encontrado
gnuhtml2latex: commande introuvable
gnuhtml2latex: command not found
gnuhtml2latex: käsku ei ole
gnuhtml2latex: không tìm thấy lệnh
gnuhtml2latex: komanda nerasta
gnuhtml2latex: Kommando nicht gefunden.
gnuhtml2latex: kommandot finns inte
gnuhtml2latex: komut yok
gnuhtml2latex: nie znaleziono polecenia
gnuhtml2latex: níor aimsíodh an t-ordú
gnuhtml2latex: no se encontró la orden
gnuhtml2latex: no s'ha trobat l'ordre
gnuhtml2latex: opdracht niet gevonden
gnuhtml2latex: parancs nem található
gnuhtml2latex: perintah tidak ditemukan
gnuhtml2latex: príkaz nenájdený
gnuhtml2latex: příkaz nenalezen
gnuhtml2latex: команда не найдена
gnuhtml2latex: командата не е открита
gnuhtml2latex: 命令找不到
gnuhtml2latex: コマンドが見つかりません