If you haven't yet fixed the problem, this worked for me when I got that error message. You don't have to backup your hard drive or reinstall Mac OS X.
1. Find and insert the Mac OS X install disc.
2. Restart your computer, holding the C key
3. Your Mac will boot from the install CD, DO NOT perform a new install
4. Select disk utility from the utilities menu at the top of the screen
5. Select Macintosh HD and under the "First Aid" tab select "Verify Disk"
5. You will be prompted to enter your password
6. Let it go through the process, when (if) any errors come click "Repair Disk"
--If you do not get any errors then this probably isn't your problem
7. Let it finish repairing the hard disk drive, then restart your Mac.
8. Open up Bootcamp and retry.
This may or may not work, I just know that it worked for me.
