mpegcat: 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/mpegcat - from package: gopchop

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

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