mid3cp: 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/mid3cp - from package: python-mutagen

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

Error in other languages:
mid3cp: bevel nie gevind nie
mid3cp: comandă negăsită
mid3cp: comando não encontrado
mid3cp: commande introuvable
mid3cp: command not found
mid3cp: käsku ei ole
mid3cp: không tìm thấy lệnh
mid3cp: komanda nerasta
mid3cp: Kommando nicht gefunden.
mid3cp: kommandot finns inte
mid3cp: komut yok
mid3cp: nie znaleziono polecenia
mid3cp: níor aimsíodh an t-ordú
mid3cp: no se encontró la orden
mid3cp: no s'ha trobat l'ordre
mid3cp: opdracht niet gevonden
mid3cp: parancs nem található
mid3cp: perintah tidak ditemukan
mid3cp: príkaz nenájdený
mid3cp: příkaz nenalezen
mid3cp: команда не найдена
mid3cp: командата не е открита
mid3cp: 命令找不到
mid3cp: コマンドが見つかりません