2 questions !

Hello all, I wondered if someone could answer me to my questions.

1.Can i use Serial Key/Number from Mount and Blade the first part for Mount and Blade Warband??

2.What does Error''Incorrect Serial Number '' means ?? when i try to log in to some of the servers it shows up i dont understand it.

Yup, I'm interested too about these questions. 

1. No.

2. Probably that you're still using the beta key which does not work for Warband.