it says that the serial will be sent to me next week
Yeah, that happened to me too. I read somewhere that it has something to do with the high volume of sales over the weekends. I guess they must need to request more from the publisher or something. Definitely a bummer, but worth the wait for saving $22.
BTW, once you do get your serial you can go to the Fantasy Wars website and DL the map editor for free. Also, there are no patches either, just the editor.
To those who are still curious about the game: I've played through the demo twice and really enjoyed it. It's a very methodical, slow moving TBS that needs careful planning in order to master. It's a great change of pace from the HOMM style games that allow you to amass a huge army and steamroll opponents. Your units level up, so if you lose one it can really hurt. Probably the closest comparison I can think of gameplay-wise is the Fire Emblem games, if you've played those.