mprandomwalk: 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/mprandomwalk - from package: mpdtoys

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

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