Acid is right... try a search before you post, as it helps to alleviate duplicate questions and confusion.
But since you asked and this thread is already here, i will help.
NTFS is not fully supported in Linux yet. I believe that a read driver works fine, but the read/write driver is VERY experimental, and can and has caused file corruption on NT and like drives.
But if you still want to try it, then you need to compile a new kernel with NTFS file drivers loaded in.