Can't get IP address from range expander on SOME devices

Can't get IP address from range expander on SOME devices

I installed a Linksys WRE54G range expander. It's working fine with my Windows 7 laptop, but not so much with my Palm Pre and my Ubuntu netbook. Both of those devices act the same... they see the wireless network, say they're "connecting" for a long time, then finally fail saying they can't get an IP address.