A Co-Worker Is Acting Wierd

What do you do when a co-worker is acting wierd? And I don't mean just any co-worker, but the one you are planning to take over a business with. I ask her if everything is OK, and she says yes. I ask her if I have annoyed her in some way, and she says no. But she still does not say anything to me, and she acts as if she is trying to avoid me. Just plain wierd. Granted, she is sort of like this with everyone, but it seems more pointed with me. I just don't think this is good business. You should be polite and friendly with your co-workers, even if something is bothering you. It makes me wonder about the future, and how well she would work out in the long run if this is her MO. More about this another time.