The last time i used Ad-Aware on my test system (May 17th, 2008), i got this:

Looks like the new updates are no longer compatible with the old AA106

You can download the last update known to work here

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        Someone recently brought to my attention the fact that the onboard updater in Ad-Aware version 1.06 no longer works. The server just refuses to send the file when it identifies an older updater, yet the update is still compatible. I created my own updater a while back because i found the onboard updater way too slow. I guess now is a good time to share it with my visitors. You can download it here. The file is self-extracting, read instructions in Readme_updater.txt. Run the updater before you start Ad-Aware to make sure the latest update gets loaded.

        If you prefer, definition updates for Ad-Aware can be performed manually by downloading the latest defs.zip and unzipping it in the same folder as the Ad-Aware.exe executable, before starting Ad-Aware.