I have a Dual 2GHz PowerPC G5 running Mac OS 10.3.9 with a newly installed Airport Extreme Card. I am trying to get it to connect to my Linksys Wireless Router (WRTP54G). I can only connect to the wifi if I leave it unsecured. I know I’m using the correct WEP key and my Sony laptop can sit right next to the Mac and connect will fill signal strength. Are there some settings I need to have configured to get this to work?