My MBP won't detect my AirPort Express from 18 inches away.

So. I've been very frustrated with my Airport Express.

I have an AirPort Extreme as my base station, and I wanted to extend the network a little bit. So I bought an AirPort Express, thinking that everything would go as smoothly as it did with the Extreme. Boy was I wrong.

First, I set up the Extreme as a WDS base station. Then, I plugged in the brand-spanking new Airport Express where I get full signal strength from my base station. My MBP is within 18 inches of my new techno-toy. Well, I set it up to work to extend my network. Fantastic! After I finished, the green light was on everywhere. Except the network coverage hadn't changed. Hmmmmm.

I go into AirPort Utility, and I cannot detect the new Airport Express. Re-scan a few times. Nothing. I reset and set it up again. Nada.

Do you guys have any ideas? Please help!