sitesummary-client: 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-client - from package: sitesummary-client

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

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