I've had the same problem with my router off and on for the two years that I've owned it.
It has nothing to do with the computer / laptop / ipod touch / whatever you are trying to connect with. (As long as it has a normal web browser with scripting - I've noticed the Sony PSP can't load the setup, because it does no scripting.) I have a home network with a variety of devices attached, both through cables and through wireless.
The problem is inside the router. The setup pages are WEB pages, and are being served from a web server inside the router. The setup is made up of web pages with names like this:
Now if I do a complete reset of the router, following the manufacturer's instructions, then I can access those setup pages at 192.168.1.1.
As time passes (months), if I log in to those setup pages, I notice that the pages begin to degrade. Buttons are missing. The layout becomes screwed up. I've seen previous posters mention this earlier in this thread. Strangely the router continues to work just fine. It has no other problems, it just begins to lose it's ability to serve up it's own setup web pages.
Eventually, the setup pages will not load up at all. That is where I am at today. I am plugged directly into the router, and when I try to load up the setup it says
The connection has timed out
The server at 192.168.1.1 is taking too long to respond.
Now, I know if I completely reset the router and go through the initial setup again, it will work fine for a few months. I've been through this before, probably about four times in two years.
Why is it doing this? I do not know. I suspect there are defects in the hardware or software, because of the regularity of the problem. I wish Linksys offered an easy-to-find solution, but I am not able to find. it.