Error Resizing

When using Gparted Live CD 0.3 there is a small orange triangle icon with an exclamation listed after /dev/hda1 - my ntfs partition. I want to shrink this partition so I can make room for a ubuntu install without losing windows data or reformatting from scratch. I am given the option to resize but dragging the graphical bar to the left or right doesn't work. It doesn't move at all. The only other partition on the hd is unallocated, which I believe is used for XP System Restore information.

I have also tried using the Gparted version that comes with the ubuntu Live CD with nearly the same results. There is no orange triangle icon with an exclamation point and I am able to resize the partition, however, upon clicking apply I receive an error message saying it failed.

Computer Info:
HP Pavillion zd8000
Single 80Gb HD running Windows XP
ATI X600 Radeon Graphics
1Gb of RAM

What other information do I need to give?

Thank you.