qmp3cut: 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 Debian possible default full paths are:

/usr/bin/qmp3cut - from package: quelcom

You may install the required package with command apt-get install {package}
Error in other languages:
qmp3cut: bevel nie gevind nie
qmp3cut: comandă negăsită
qmp3cut: comando não encontrado
qmp3cut: commande introuvable
qmp3cut: command not found
qmp3cut: käsku ei ole
qmp3cut: không tìm thấy lệnh
qmp3cut: komanda nerasta
qmp3cut: Kommando nicht gefunden.
qmp3cut: kommandot finns inte
qmp3cut: komut yok
qmp3cut: nie znaleziono polecenia
qmp3cut: níor aimsíodh an t-ordú
qmp3cut: no se encontró la orden
qmp3cut: no s'ha trobat l'ordre
qmp3cut: opdracht niet gevonden
qmp3cut: parancs nem található
qmp3cut: perintah tidak ditemukan
qmp3cut: príkaz nenájdený
qmp3cut: příkaz nenalezen
qmp3cut: команда не найдена
qmp3cut: командата не е открита
qmp3cut: 命令找不到
qmp3cut: コマンドが見つかりません