Update: Still no official response from Cisco/Linksys, but Matt was kind enough to send us the official work-around that users who have reported the issue are told to use. We've included that for you below.
Update 2: Cisco responds!
[Thanks to everyone who sent this in]
DMA workaround- DMA hangs/freezes as soon as it connects to the Internet
1. Remove the power cable first from the DMA
2. Hold down the reset button
3. Plug the power cable back on and keep holding the reset button for at least 15 seconds as it's booting up
4. Release the reset button and wait until the LED on the DMA becomes solid.
5. Once the DMA menu comes up on the screen go to :
• Network>Set up Network> select Wired or Wireless (your preference)
• If you are setting up the DMA wirelessly select your SSID from the list and enter your security key when prompted ( if you have encryption on the wireless router otherwise click Next if you don't have one. (If you do not know what your passphrase key is you will need to contact your vendor of the wireless router to obtain that information. For Linksys or Cisco Consumer routers, login from a computer that is on the network to http:192.168.1.1 (or whatever your router's IP address is) enter the router's username and password, go to the Wireless page and then click on Wireless Security, this is where your passphrase key will be, remember it's case sensitive.
• When you get to the Address Setting page select Manually>enter a static IP that is withint your network range but for DNS use 18.104.22.168 and click Next until you click Finish.
6. Your DMA should be working now.
Note: You may not need to reconfigure your DMA through your Vista computer, however should the DMA have a problem bringing up Windows Media Center or it gives you a key when you clicked on the Media Center button on your remote, you will need to reconfigure it again.
Reconfiguring the DMA for Windows Media Center
1. Go to the Vista computer that it was associated to before it stopped working.
2. Open Windows Media Center >Task>Settings>Extender>and select Reconfigure
3. You will be prompted for the key that it generated on the TV.
4. Enter the key and just run through the wizard. Once it's complete launch Windows media Center on the TV now.