I merged this thread and the other thread you made and put it in 2005 General Issues.
I ran both Norton AntiVirus and Ad-Aware SE on my HD, and it didn't find any.
I also ran used Norton to check that exact file, and it wasn't infected it said...
[edit]: I also now installed the patch and ran Norton again, and still nothing.
What is the name of the trojan that was found anyway? Perhaps your PC was already infected prior to the completion of your patch download. Maybe it's a virus and it's already doing its payload.