Are you sure that's EXACTLY what Spybot's message is saying? I haven't seen that type of message before, BUT I have seen the message which suggests that Ad-Aware may detect that some of Spybot's reference files are spyware. In addition, there is a warning notice that some software may not run after removing spyware and advertising robots, but that shouldn't stop the program from working correctly. Simply choose to recognize the fact but to move on, should allow the installation to proceed correctly and work fine.
Both programs will "play together" well.
Hope this helps.
Since switching to Spybot, I haven't run Ad-aware since 5. After hearing from people running both(knowing it was a good idea), I finally got around to downloading Ad-aware 6.0. After installing it, I click to run it. I got a pop-up from Spybot saying that because of how Ad-aware operates, they were incompatible. Uninstalled for now. Anyone else have this happen? chuck