parser3: 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/parser3 - from package: parser3-cgi

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

Error in other languages:
parser3: bevel nie gevind nie
parser3: comandă negăsită
parser3: comando não encontrado
parser3: commande introuvable
parser3: command not found
parser3: käsku ei ole
parser3: không tìm thấy lệnh
parser3: komanda nerasta
parser3: Kommando nicht gefunden.
parser3: kommandot finns inte
parser3: komut yok
parser3: nie znaleziono polecenia
parser3: níor aimsíodh an t-ordú
parser3: no se encontró la orden
parser3: no s'ha trobat l'ordre
parser3: opdracht niet gevonden
parser3: parancs nem található
parser3: perintah tidak ditemukan
parser3: príkaz nenájdený
parser3: příkaz nenalezen
parser3: команда не найдена
parser3: командата не е открита
parser3: 命令找不到
parser3: コマンドが見つかりません