sisu-pg: 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-pg - from package: sisu-postgresql

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

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