yuvfps: 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/yuvfps - from package: mjpegtools

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

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