rollchk: 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/rollchk - from package: dnssec-tools

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

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