No, it's the other way around.
MD4Bush was targetting Steffen at his work, and someone there used Steffen's computer (while he was away) to see where he'd been surfing. That's how MD4Bush knew to come to Free Republic to bait Steffen.
I'm still a little confused - MD4Bush was able to plant someone inside Steffen's office? And when Steffan wasn't around, this person broke into Steffen's computer and relayed what he found back to MD4Bush? Do we know who this person that broke into Steffen's computer is?