rollset: 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/rollset - from package: dnssec-tools

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

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