tentacle_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/bin/tentacle_client - from package: pandorafms-agent

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

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