Problem rendering file when error using autocomplete field

Is there a way to render a file from within Rails app so it is
displayed in a new browser tab/window??

I have an auto_complete field where users can enter letters to search
for last name. If some sort of database
error occurs while entering data in this field, the error is captured
but the html file that should be displayed (a generic error page) is
not being rendered in the browser. I can see the render command being
issued in the Mongrel console window… And in the current view in
the browser, some of the fields shift to the right. So it’s like
the browser is trying to render something directly within the page.
Thought it might be worth trying to render
the error page to a new tab to see if that would work.

Unless anyone has seen a similar problem, and knows how to capture
errors and display error page when
using an auto_complete field??