I'm going to instal FC 7 on my pc as second os , but what is the important package should I install ? (not include X - free , graphical interface or common we know) . Like libc++ and so .
Replace libc++ with whatever it cannot find. Yum will then tell you what package you will provide the missing part.
yum install libc++
One gotcha that you have to look out for is that some things you will need package-devel for when it says missing package. This is usually when you are compiling things.
When you post error messages try to get the exact message (cut and paste when possible) as subtle differences can be very important.