When the browser fails to find the next page, what error do you have (see in log of your HTTP Server), sometime, looking in the log could help to relove problems...
For this kind of probleme, I'don't know if I had the same, but when I just made a change in source code, and restartin de WebSite (refresh) without restarting browser, The browser showed me the saved page in the Temp Dir. or sometimes, display that the page was not available (error 404)...