if you have a book you will see the possible causes for code 41
they are a faulty regen contactor, or faulty wiring associated with it's circuit, or faulty logic card.

being that the one you got from the cat dealer has been opened from the sounds of it i would not trust it. Take it back and make them give you one that has not been opened. Sounds like they gave you one that was put back on the shelf to me.