The folder "iTunes" is on a locked disk...

I am getting the following message when I try to open up my iTunes. "the folder "iTunes" is on a locked disk or you do not have write permissions for this folder". Can someone please help me figure out how to get my iTunes back?

My husband had set up our XBox 360 as an extender from our computer and I'm sure it stems back to this - he did something so that the Windows media center would recognize our iTunes files and play through the XBox - ever since then I haven't been able to open my iTunes. I did disconnect the XBox as an extender and have figured out how to stop having the media center look for my iTunes files as a source of music.

Should I try to reinstall iTunes?