bluetooth_scan: 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/lib/plainbox-providers-1/checkbox/bin/bluetooth_scan - from package: plainbox-provider-checkbox

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

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