Safe wire/Code entry

Ok I've tried searching and came up with nothing due to the fact when you search safe wire or safe pin everything with just those words comes up. Now here is my problem before I installed my sub and amp I would get the safe pin error message and have to enter in the code. Now sometimes it wouldn't accept the code and I would have to turn off the car for about half hour. Now that I installed a sub and amp it does it a LOT MORE. Again sometimes it accepts the code and sometimes I have to wait a while. I installed the amp with a hi/lo converter. I tapped in the rear speakers and the remote wire (white wire on the amp harness). Why the hell is this happening and how do I fix it cause it's getting real annoying. Like I said I've looked it up in the quick links and don't really understand what I need to do.

" 20) SAFE wire / Entering 4 digit security code:
In the black 8 pin connector (III), pin location #5 (in some audi's this slot is open; in others it is used as a remote lead for a power antenna) is for the SAFE wire (which requires a constant 12v source; NOT ignition 12v). "