varnishreplay: 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/varnishreplay - from package: varnish

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

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