qmpdclient: 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/qmpdclient - from package: qmpdclient

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

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