[Plugin: NextGEN Gallery] Unable to use Lightbox

I’m using Nextgen (it’s great by the way) and I’ve been using it with Thickbox and it’s worked okay but I’ve tried it with Lightbox2 and Slimbox and neither seem to work. When I click on the thumbnail it just opens the picture in a new window (in the top right corner).

It has added the “rel=”lightbox” attribute so I’m not sure why it’s not working? I’ve checked the path to the javascript file from the header code and all appears to be okay there so I’m a bit lost on this one.

Any help would be very much appreciated.