If you are on a Mac, press command shift G and in the box type /users and then go, next click on your user name and navigate to netbeansprojects and open it. Then delete the ones in there that are causing problems. You can then create your project.
Note: I had moved my wordpress folder to my desktop trying to figure this out, so I dropped it back into the origional location and it works fine. So if you did this, just replace the wordpress folder after deleting the problem projects from the netbeansprojects folder and its contents back to the original installation folder.
Hope this helps...:)