racoon2-pskgen: 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

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/racoon2-pskgen - from package: racoon2

You may install the required package with command yum install {package}
Error in other languages:
racoon2-pskgen: bevel nie gevind nie
racoon2-pskgen: comandă negăsită
racoon2-pskgen: comando não encontrado
racoon2-pskgen: commande introuvable
racoon2-pskgen: command not found
racoon2-pskgen: käsku ei ole
racoon2-pskgen: không tìm thấy lệnh
racoon2-pskgen: komanda nerasta
racoon2-pskgen: Kommando nicht gefunden.
racoon2-pskgen: kommandot finns inte
racoon2-pskgen: komut yok
racoon2-pskgen: nie znaleziono polecenia
racoon2-pskgen: níor aimsíodh an t-ordú
racoon2-pskgen: no se encontró la orden
racoon2-pskgen: no s'ha trobat l'ordre
racoon2-pskgen: opdracht niet gevonden
racoon2-pskgen: parancs nem található
racoon2-pskgen: perintah tidak ditemukan
racoon2-pskgen: príkaz nenájdený
racoon2-pskgen: příkaz nenalezen
racoon2-pskgen: команда не найдена
racoon2-pskgen: командата не е открита
racoon2-pskgen: 命令找不到
racoon2-pskgen: コマンドが見つかりません