sisu-harvest: 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/sisu-harvest - from package: sisu

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

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