I got a problem with the Thematic Widget in Flex. As you see in the attachment, the main Panel doesnt display the different classes. All classes are null-null...
I do not have a good answer for you, however, can commiserate as I was having the same problems. I suspect a few things; having the service defined wrong, having the variable defined wrong, needing to upgrade the widget version, just random gremlins in my old server.
Regardless, my plan to address involved moving from an old version of the widget, 3.1, to either 3.5 or 3.6. I'll post back afterwards if that fixes "our" problems.