debmirror: 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 CentOS possible default full paths are:

/usr/bin/debmirror - from package: debmirror

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/debmirror - from package: debmirror

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

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