events.html: command not found

Have You tried accessing the binary with the full path?

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/share/doc/python-celery-doc/html/_modules/celery/bin/events.html - from package: python-celery-doc

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