Trouble with BOOT CAMP when Partitioning PLEASE HELP!!

I have a black macbook and I am trying to install windows vista via bootcamp. The problem Im having is that when I try to partition the hard drive I get an error message saying that it cant partition the drive because there are files and folders that it cannot move and then tells me to use disk utitility to backup and then try again. One problem I dont really know how to do that. And what do I have to do to get it to work for me. Please help me out with this and I appreciate all of your help in advance.