musixflx: 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 CentOS possible default full paths are:

/usr/bin/musixflx - from package: texlive

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

On Debian possible default full paths are:

/usr/bin/musixflx - from package: musixtex

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

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