Unless you've filled your hard drive and cleared out 60 GB of space to use with Boot Camp, you should probably make an appointment with an Apple Genius or call the support line.
If you filled the hard drive and then cleared out some space, you probably don't have 60 GB of contiguous space at the end of the drive. Contiguous space is required for the partitioning. The only way to fix that is reformatting the drive. Time Machine backups are a great solution for that.