httexi: 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/httexi - from package: tetex-tex4ht

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

On Debian possible default full paths are:

/usr/bin/httexi - from package: tex4ht

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

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