mucous: 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/mucous - from package: mucous

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