linkextractor: 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/linkextractor - from package: libhtmlparser-java-doc

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

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