nextgen-gallery – can't get to show slideshow

Hi, I haven’t made it very far with nextgen-gallery. I can get a list of thumbnails to show, but I just want a slideshow and so when I try, the “loading” timer just runs indefinitely. It’s as though it can’t find the gallery photos, but yet the images show in list view.

I have gallery folder permissions set to ‘write’. Anyone have troubleshooting tips?

By the way, my site is running the Gantry Framework but there doesn’t seem to be any compatibility issues.

Thanks,