2html: 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 CentOS possible default full paths are:

/usr/bin/2html - from package: xml2

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/2html - from package: xml2

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

Error in other languages:
2html: bevel nie gevind nie
2html: comandă negăsită
2html: comando não encontrado
2html: commande introuvable
2html: command not found
2html: käsku ei ole
2html: không tìm thấy lệnh
2html: komanda nerasta
2html: Kommando nicht gefunden.
2html: kommandot finns inte
2html: komut yok
2html: nie znaleziono polecenia
2html: níor aimsíodh an t-ordú
2html: no se encontró la orden
2html: no s'ha trobat l'ordre
2html: opdracht niet gevonden
2html: parancs nem található
2html: perintah tidak ditemukan
2html: príkaz nenájdený
2html: příkaz nenalezen
2html: команда не найдена
2html: командата не е открита
2html: 命令找不到
2html: コマンドが見つかりません