gst-feedback-0.10: 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 CentOS possible default full paths are:

/usr/bin/gst-feedback-0.10 - from package: gstreamer

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/gst-feedback-0.10 - from package: gstreamer0.10-tools

You may install the required package with command apt-get install {package}
Error in other languages:
gst-feedback-0.10: bevel nie gevind nie
gst-feedback-0.10: comandă negăsită
gst-feedback-0.10: comando não encontrado
gst-feedback-0.10: commande introuvable
gst-feedback-0.10: command not found
gst-feedback-0.10: käsku ei ole
gst-feedback-0.10: không tìm thấy lệnh
gst-feedback-0.10: komanda nerasta
gst-feedback-0.10: Kommando nicht gefunden.
gst-feedback-0.10: kommandot finns inte
gst-feedback-0.10: komut yok
gst-feedback-0.10: nie znaleziono polecenia
gst-feedback-0.10: níor aimsíodh an t-ordú
gst-feedback-0.10: no se encontró la orden
gst-feedback-0.10: no s'ha trobat l'ordre
gst-feedback-0.10: opdracht niet gevonden
gst-feedback-0.10: parancs nem található
gst-feedback-0.10: perintah tidak ditemukan
gst-feedback-0.10: príkaz nenájdený
gst-feedback-0.10: příkaz nenalezen
gst-feedback-0.10: команда не найдена
gst-feedback-0.10: командата не е открита
gst-feedback-0.10: 命令找不到
gst-feedback-0.10: コマンドが見つかりません