tripwire-setup-keyfiles: command not found

Have You tried accessing the binary with the full path?

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/sbin/tripwire-setup-keyfiles - from package: tripwire

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