What can cause a persistent “Reload the page to get source for” error in firebug?

Question

I\'m trying to debug the javascript of a specific page, and I keep seeing

Reload the page to get source for page.htm in Firebug.

On Chrome, I\'m

Answer 1

I have this problem once.
the solve for me is the host name

page url: http://localhost
request url: http://192.168.0.1