Downloaded an opensource sample Iphone project and when I compiled, everything is OK. This project has alot of C files. So, I try to rebuilding this project from scratch just to see if I can duplicate it. I make sure all the inlcudes files there, the path is correct, all the libraries there. I check original project settings and make sure if they have any specific search path and I need to follow. Anyway, I follow the exact settings but this time my duplicated project got some 1500 errors. alot of them generated from inside those C files. So, what's wrong? everyone got some tips on that why I got so many errors? I followed everything I follow from the original project.