sitesummary-nodes: 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/sbin/sitesummary-nodes - from package: sitesummary

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

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