That IP opened right up for me.
Try the following:
Remove AC power from modem
Remove AC power from router.
Plug modem back in and wait for it to boot completely before next step.
Plug Router back in and allow to boot completely.
Try open the page using the IP posted above so as to avoid the need for DNS data.
Did it open ?
If not, try another browser.
If not then, try to disable Web Accelertaion
Are you on a HN9000 or an HT1000/1100 modem?
Have you done the "hard reset" of both modem and router?
The definition of a 404 is this:
The 404 or Not Found error message is a Hypertext Transfer Protocol (HTTP) standard response code, in computer network communications, to indicate that the client was able to communicate with a given server, but the server could not find what was requested.
You are welcome.
There is a lot of "stuff" that can get stored by both the modem and the router. A hard reset (30 or more seconds) will cause them to dump the data and "refresh".
Electronics 101: If its acting strange, reboot it