dump-mixers: 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/dump-mixers - from package: xawtv

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

On Debian possible default full paths are:

/usr/bin/dump-mixers - from package: xawtv-tools

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