I've written about a lot of problems related to dlls and spam spewing out of my servers. Maybe this was the source:
A hack with it's own virus checker
This piece of malware is spewing out all that stock spam you've possibly been seeing lately with some pretty advanced tactics.
The article states that the trojan uses peer-to-peer technology to communicate with command and control servers, however it does not tell you how it got on the box in the first place.
This software is making some use of dlls...a major annoyance if you read my previous posts.