dbus-send: 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:

/bin/dbus-send - from package: dbus

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

On Debian possible default full paths are:

/usr/lib/x86_64-linux-gnu/dbus-1.0/debug-build/bin/dbus-send - from package: dbus-1-dbg
/usr/bin/dbus-send - from package: dbus

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

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