ppi2html: 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/ppi2html - from package: perl-PPI-HTML

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

On Debian possible default full paths are:

/usr/bin/ppi2html - from package: libppi-html-perl

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

Error in other languages:
ppi2html: bevel nie gevind nie
ppi2html: comandă negăsită
ppi2html: comando não encontrado
ppi2html: commande introuvable
ppi2html: command not found
ppi2html: käsku ei ole
ppi2html: không tìm thấy lệnh
ppi2html: komanda nerasta
ppi2html: Kommando nicht gefunden.
ppi2html: kommandot finns inte
ppi2html: komut yok
ppi2html: nie znaleziono polecenia
ppi2html: níor aimsíodh an t-ordú
ppi2html: no se encontró la orden
ppi2html: no s'ha trobat l'ordre
ppi2html: opdracht niet gevonden
ppi2html: parancs nem található
ppi2html: perintah tidak ditemukan
ppi2html: príkaz nenájdený
ppi2html: příkaz nenalezen
ppi2html: команда не найдена
ppi2html: командата не е открита
ppi2html: 命令找不到
ppi2html: コマンドが見つかりません