My 2006 Audi A6 starts up fine. However, I'm getting the EPC warning light. Took it to a local shop (not the dealer), they ran the diagnosis and said it was my Shift interlock assembly. Pretty much a black and white box that the gear shifter sits in. They ordered the part from a local Audi dealer and replaced it this week and the next day while out eating lunch I got in my car, started it and again the EPC light stayed on and I could not get my car out of gear.

Has anyone heard of this before?

If you mean "out of park" it is most likely a problem witht the park lock out. Eithe adjustment, bad solenoid or bad brake light switch. I'd start with the switch - easy change - and go from there.