The remote locking has failed on Sept 2002 A4.
I can unlock all doors ONLY, by first opening the drivers door with the key, then inserting and turning the ignition key.
This operation opens all doors.
To lock, I close all doors and lock with the drivers door key. All doors lock.
The remote on both keys will not operate anything and that inclueds window operation and just the boot..

john Knight, December 2010