+1Okay, so I think I have the simplest solution yet.
I restarted my computer.
However, after that, I also decided to eject the Windows 7 install disc.
I'd recommend that anyone try this first, as it seems that a lot of solutions that people have found are specific to them, and don't always apply to everybody.
Thanks!
Alright peoples, here's my solution to this problem...
I HAVE FOUND THE SOLUTION TO THIS PROBLEM:
bootcamp refuses to move the files once you partition and then undo and try to redo another partition.
the only way i have found to fix this problem is to boot your mac with the OS X installation cd. then go to the utilities at the top menu bar and select Disk Utility then the tab Partition. Change the size of your mac hd (smaller) to the desired free space you want to be freed up and select apply. Add another partition by clicking the plus sign at the lower left and call it whatever you like.
Reboot and remove the disk and go to your Utilities and select Disk Utilities. Remove the new Partition you have just created and expand your mac had back to full length. Click Apply
This way of partitioning the drive is able to move the files which Bootcamp assistant is not. Now you can open bootcamp again and select the same size for windows as you freed up for the "other" partition.
Problem solved
Guys, try running the fsck command as I posted above- it worked twice for me after defragging and clearing up space, etc. didn't work.
Let us know if it worked, it was a lifesaver for me.
I had the same problem with boot camp-assistant not being able to move some files, thus, not creating the partition needed for windows.
What did it for me, was the same aflick86's solution. booting up from the OS X DVD, Fire up disk utility from the DVD, verify and repair disk permissions, verify and repair your disk. Then choose the MAC OS X HDD, not the name, but the one with the model number. go to the Partition tab, and add a new partition with the '+' sign, change the size of your partition, it is likely that it won't go as small as you want it, but it's better than reinstalling OS X, remember to choose FAT from the drop-down menu. When finished partitioning, boot into OS X and fire up the boot camp-assistant, this time it will recognize the FAT partition and ask if you want to install windows or remove the partition.