I am very new to C++/Objective C programing (but doing my best to learn it

I have a question:
I am trying to add Bullet Physics to my iPhone app. So when I create in XCode a new Window Based Application everything is fine.
Now i am trying to add the source code of Bullet (ie right click -> add existing files -> select bullet/src) and try to compile everything breaks.
Could anyone please tell me what I am doing wrong or missing?
Any help would be very appreciated...
Thanks
Gerch