parser: 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/share/doc/libhtmlparser-java-doc/examples/bin/parser - from package: libhtmlparser-java-doc

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

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