Need help with Apple Airport Express


I bought an Apple Airport Express so I can connect my Marantz SR-7007 to my wireless network. I want to use it as a wireless client. I have an iMac and AT&T uverse is my Internet provider. The Airport Express configures properly ONLY IF it is connected to the router with an Ethernet cable. I can not get it to work with the Wireless network. I've googled directions and tried everything. Can anyone help, or do I have to have an Apple tech come to the house ? Thanks
mabonn
You need to set it up to join your existing network and then enter the name and security code for your network. This should do the trick.
Thanks for your help. I spent nearly an hour on the phone with Apple tech support. Still no luck. The support tech said he would send a report to engineering and get back to me in a few days. If that doesn't work, I guess I will return it and get a Squuzebox Touch.
I second Czbbcl, you need to join existing network since AE does not work in peer-to-peer mode. You need to enter name and security code with Ethernet cable connected to your computer.
Mabonn,

Have you downloaded the most recent installer version? If you have the newest Express and are trying to sync it to your network using an outdated installer, you will experience exactly what you describe.
I finally got it working. Apple tech support called me back today and walked me thru it. When I first spoke to them Sunday , they had me connect the computer to the wrong port on the airport express. Not to impressed with that, but I am pleased that the tech actually followed up with engineering, got the correct solution, and called me back when he said he would. Thanks for all your replies. Matt