Error page redirection

Before I go back to the multilingual stuff, I need to config the site so that pages with errors redirect to a “friendly” page.

If someone sends an invite out with a malformed email address, they are getting a sql error page with no option but to hit back. This is ok, but not great. I will investigate this now. There are mods to do this and of course I could sanitize the input field. But i would rather have a catchall at this point.