iso-info: 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/iso-info - from package: libcdio

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

On Debian possible default full paths are:

/usr/bin/iso-info - from package: libcdio-utils

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

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