Client won't associate with range expander.

Hello;

I have a WRT54G wireless router, and a WRE54G v1.0 Range Expander.
Previously it all worked fine. But currently, the client will not talk
to the range expander, only to the the AP.

This results in Windows ZWC in reporting a low signal and
disconnecting. Same with the linksys utility.
..
The Range Expander shows up on the network at 192.168.1.240, and is
responding. I just do not understand why the client will not associate
with it. Using WZC client and the linksys client, they will just
associate with the actual access point. It's like the range expander
isn't even there.

The range expander has been upgraded to the current 1.06 firmware.

Any ideas are most appreciated