Pest Patrol 4 flags the Cydoor dummy that comes with Spybot-S&D as something that installs a trojan instead of removing spyware. This has even earned Certainty: Confirmed by the makers of Pest Patrol.
This dummy is not a trojan! Trojans are secretly installed files that contain malicious code. This dummy is not being installed secretly (the user is informed that the file gets replaced with a dummy), and it does not contain any malicious code (as everyone can check in the source code publicly available on its author's site)
(Reminder: the dummy is used to fool the desired software that its spyware is still there!).
You can read more details about this at the forum.