xmms2-mdns-avahi: 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/xmms2-mdns-avahi - from package: xmms2-client-avahi

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

Error in other languages:
xmms2-mdns-avahi: bevel nie gevind nie
xmms2-mdns-avahi: comandă negăsită
xmms2-mdns-avahi: comando não encontrado
xmms2-mdns-avahi: commande introuvable
xmms2-mdns-avahi: command not found
xmms2-mdns-avahi: käsku ei ole
xmms2-mdns-avahi: không tìm thấy lệnh
xmms2-mdns-avahi: komanda nerasta
xmms2-mdns-avahi: Kommando nicht gefunden.
xmms2-mdns-avahi: kommandot finns inte
xmms2-mdns-avahi: komut yok
xmms2-mdns-avahi: nie znaleziono polecenia
xmms2-mdns-avahi: níor aimsíodh an t-ordú
xmms2-mdns-avahi: no se encontró la orden
xmms2-mdns-avahi: no s'ha trobat l'ordre
xmms2-mdns-avahi: opdracht niet gevonden
xmms2-mdns-avahi: parancs nem található
xmms2-mdns-avahi: perintah tidak ditemukan
xmms2-mdns-avahi: príkaz nenájdený
xmms2-mdns-avahi: příkaz nenalezen
xmms2-mdns-avahi: команда не найдена
xmms2-mdns-avahi: командата не е открита
xmms2-mdns-avahi: 命令找不到
xmms2-mdns-avahi: コマンドが見つかりません