mergebad: 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/mergebad - from package: recoverdm

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