readmult: 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/readmult - from package: genisoimage

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

On Debian possible default full paths are:

/usr/bin/readmult - from package: icedax

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

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