buildnotify: 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/buildnotify - from package: buildnotify

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

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