lav2wav: 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/lav2wav - from package: mjpegtools

You may install the required package with command apt-get install {package}
Error in other languages:
lav2wav: bevel nie gevind nie
lav2wav: comandă negăsită
lav2wav: comando não encontrado
lav2wav: commande introuvable
lav2wav: command not found
lav2wav: käsku ei ole
lav2wav: không tìm thấy lệnh
lav2wav: komanda nerasta
lav2wav: Kommando nicht gefunden.
lav2wav: kommandot finns inte
lav2wav: komut yok
lav2wav: nie znaleziono polecenia
lav2wav: níor aimsíodh an t-ordú
lav2wav: no se encontró la orden
lav2wav: no s'ha trobat l'ordre
lav2wav: opdracht niet gevonden
lav2wav: parancs nem található
lav2wav: perintah tidak ditemukan
lav2wav: príkaz nenájdený
lav2wav: příkaz nenalezen
lav2wav: команда не найдена
lav2wav: командата не е открита
lav2wav: 命令找不到
lav2wav: コマンドが見つかりません