dwww-txt2html: 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/sbin/dwww-txt2html - from package: dwww

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

Error in other languages:
dwww-txt2html: bevel nie gevind nie
dwww-txt2html: comandă negăsită
dwww-txt2html: comando não encontrado
dwww-txt2html: commande introuvable
dwww-txt2html: command not found
dwww-txt2html: käsku ei ole
dwww-txt2html: không tìm thấy lệnh
dwww-txt2html: komanda nerasta
dwww-txt2html: Kommando nicht gefunden.
dwww-txt2html: kommandot finns inte
dwww-txt2html: komut yok
dwww-txt2html: nie znaleziono polecenia
dwww-txt2html: níor aimsíodh an t-ordú
dwww-txt2html: no se encontró la orden
dwww-txt2html: no s'ha trobat l'ordre
dwww-txt2html: opdracht niet gevonden
dwww-txt2html: parancs nem található
dwww-txt2html: perintah tidak ditemukan
dwww-txt2html: príkaz nenájdený
dwww-txt2html: příkaz nenalezen
dwww-txt2html: команда не найдена
dwww-txt2html: командата не е открита
dwww-txt2html: 命令找不到
dwww-txt2html: コマンドが見つかりません