I’m having the same issue on a WP 3.0 install. I loaded the NexGen slideshow widget to my sidebar and it works sometimes, but not always. I’ve noticed that it does not like display intervals less than ten seconds per slide but even at 10 seconds it is intermittent.
I’m not sure if I have missed a setting, but I did also notice that the slideshow doesn’t always work on the developers site either, see the sidebar down low on this page
I am using the gallery on a few of my pages and it works fine. I am just struggling with the slideshow widget. The developer states on his web site that he will try to respond to issues posted here… hoping he visits soon.
Thanks!