extract++: 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/extract++ - from package: swish++

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

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