Help connecting to wireless network

need help connecting to a wireless network

I am sure this is not the first time that this has been asked but I need help connecting to a wireless network. I have just set up a wireless network in my home and when I try to connect my mac laptop to it I get this message:

Status: Connected to "Ativa54g"

This is the name of the network but when I try to load my browser (Mozilla) I get this this message

Address Not Found

I know the address is correct because it will connect fine when I use the built in ethernet connection. The Signal level on the airport utility is a strong as it can get. I have had this problem almost every time I have ever tried to connect to a wireless network and I know that it is a simple fix because I have fixed it several times but for the life of me I can not remember what it is that I have done in the past that fixed this problem. Does anyone have any ideas?

Does your WiFi Router using WEP, WPA or WPA2 Encryption? Have you entered the correct key?

If you click on System Preferences, Network, Airport, Advanced, TCP.IP what IP address do you see?

WPA
and apparently airport has no IP address

Are you putting in the WPA key correctly? Is Airport set for WPA?

Yes and yes. For some reason the security setting keeps changing from WPA to WPA2 Personal

I have just set up a wireless network in my home and the Internet Connect Summary for Airport says that I am connected to the network but I can't get my browser to find my home page (I know that it is entered correctly because it finds it with no problem when I use he built in ethernet and connect to my modem directly with a cable). ANy ideas?

Are you using a router? If so, do you have a secure link between the router and your machine? Need more info. But it does appear to be either a security issue or improper wireless setup - given that everything works OK when hooked via ethernet.

Be sure to read the forum "sticky post" regarding Airport and wireless.

Regards.

NOTE: Merged crossposts