Hello. I have installed NextGEN Gallery and uploaded my first (and only) gallery with no problems displaying thumbnails and using Thickbox effects, however, the integrated slideshow is not working. I've placed imagerotator.swf (and even all the other files in the zip) in multiple locations such as wp-content/uploads, wp-content/plugins/nextgen-gallery, and wp-content/gallery/gallery with no success. The preloader just keeps turning and turning and turning with no resulting display.
I have Googled the issue, and am a fan of RTFM, but none of this seems to have any information about this problem. You can see the result at http://djsosmooth.com/?page_id=28 -- this starts with the thumbnails all on one page, then if you click on "Play Slideshow" above the thumbnails, you can see what I'm talking about. The current location that's being used for imagerotator.swf is 'wp-content/uploads/imagerotator.swf'.
Hope this helps. Thanks alot.