pymecavideo: 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/pymecavideo - from package: python-mecavideo

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