i have been trying to create NTSF partitions inside ubuntu to install my windows 7 ultimate edition back but GParted dont work or at least dont let me do anything on this version of ubuntu ( 12.04 LTS 32 bits ) and i dont want to wipe the drive to install windows back and then install ubuntu in dual boot because is the same im trying to do but doing it is a longer process
Boot into your LiveCD or LiveUSB that you used to install Ubuntu and use that partition editor. You may be running into issues if you are trying to edit a partition that is being used. By running GParted from the LiveUSB, you are freeing the volume that you are editing, so you shouldn't have any problems.
When you are done installing Windows, you will need to boot into the LiveCD/USB again to restore the Grub bootloader. Below is a link that will help you if you will need it: