How to add a dynamic data in erro pages

The pages are located in public/. You could use your own error
controller. Simply remove 500 and 404.html in public/ and set the
correct routes to match your error controller.

lg // andreas

But how can i add a dynamic data in it?
can you tell me how to set in my own directory? please

I think I was pointing you in the wrong direction. If you want dynamic
data in your 500 error page you will need to rename public/500.html
into 500.erb and add

def rescue_action_in_public(exception)
    render :file => 'public/500.erb'
end

to your application.rb. This will render the 500 page based on erb..
Lets say you have a current_user method which points to the currently
logged in user you could write:

Dear, <%= current_user.name %>.
An error has occured.. Please stay tuned..

Hope this helps?!

lg // andreas

Thanks Andreas. This is very helpful for me.