More than likely the reason you can not get a valid IP from your access point is because of either a problem with a mismatched
ESSID/SSID/Network Name and/or
WEP key...
Wireless Encryption troubleshooting...
http://www.practicallynetworked.com/...ss_encrypt.htm
Mixing Encryption levels...
http://www.practicallynetworked.com/.../mixed_wep.htm
WEP Key generator...
http://www.warewolflabs.com/portfoli...kg/wepskg.html