btreannounce.bittorrent: 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/btreannounce.bittorrent - from package: bittorrent

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

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