musca: 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 CentOS possible default full paths are:

/usr/bin/musca - from package: musca

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