Load it with the unbrick code on (talk to Maniac), and with a fresh town (see DsPet's sample town from AiboHack.com).
Is the time set correctly?
I only think this way because if your time is around the bright nights, and you have many trees and whatnot, the bright nights won't let you load your game. This used to happen to me. I removed trees/rocks and whatnot, and it loaded fine.