To everybody reading this post -

I peered into my locked 2006 A6 Avant yesterday while parked in the driveway and noticed that the dash/idiot lights were on.
Key FOB battery is good but the car would not respond to the unlock command.
What makes the situation worse & interesting is this, the manual steel key blade will not unlock the driver's door.
The old-school key turns as it should but the door neither unlocks or re-locks.

Back ground story:
Two weeks ago I installed a new battery in the car. I then drove the car for a week after that installation. No hiccups.
I did have to use the steel key to unlock the door prior to replacing that dead battery. The steel key worked as it should, then.
Also, during the battery replacement, I also replaced the right outside corner tail/turn signal assembly (unique to the wagons Vs. sedans).
The LED's stopped working in that assembly. The replacement assembly worked perfect.

I'm most curious as to why the steel key won't unlock the driver's door.
Would anybody know this answer?

I've read that I could put power to the starter +post along with the appropriate ground connection elsewhere and that should energize the electrical system.
Still, the fact that the manual key cannot unlock the door is a head-scratcher. I don't believe any lock or door handle mechanism is broken, especially since I just recently relied on it to work.

Thank you to all in advance.