will_ruby_raise: 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/will_ruby_raise - from package: will-crash

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

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