Help Wanted: Identify these security nuggets

I've recently come across a couple of incidents with some odd data. If anyone out there knows the who, what, where or why of these datum let me know at matt dot richard at gmail dot com. I'll post any reasonable explanation.

User Agent: "DGD (AutoProxy4)" or just "DGD"
User Agent: "digit_may2002"
DLL: ddabx.dll (attaches to 3 random system processes sometime during the boot process)