What OS? It's most likely firewall software blocking you from accessing the configuration. If she has pop-up blockers, disable them too. Open up a command prompt and type:
ping
www.yahoo.com
If you get 4 replies, the connection to the router is ok, and something on her system is blocking you from accessing the configuration page. Try from another computer if you can't disable the firewall/pop-up/etc. on that PC.