funny - I had the exact same problem this weekend, drove me so mad!! But finally, I figured it out ... it had something to do with the MAC addresss ...
I have a linksys BEFRS41 so I'm not sure if it works. Basically, I had to reset the router. What I was doing wrong was that I hit the reset button and let go, the correct way to reset the router was to hold the button, until the red light comes on then goes off then you release the reset button. Afterwards it worked, I was able to access the 192.168...
hope this helps, cuz I was really to take a baseball ball and destroy that stupid router ...