Working with jcrop: png - black image

I am trying to use this jquery on my website: http://deepliquid.com/content/Jcrop.html

it is basically a tool that allows you to "cut" images. It works great since I'm working with pngs (either with a transparent background or not); if i try to cut png, the new script image is completely black.

I found some links with people having my problem and they were prompted to put this setting: bgColor: "transparent" not black and other solutions, but nothing works with me.

Has anyone used this plugin and faced the same problem? does anyone have a workaround?

thank!