ikiwiki-hosting-web-backup: 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/bin/ikiwiki-hosting-web-backup - from package: ikiwiki-hosting-web

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