activation-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 CentOS possible default full paths are:

/usr/bin/activation-client - from package: libbonobo

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/activation-client - from package: libbonobo2-bin

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

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