Enter a topic file name in the Default Topic field in the first window of the Generate wizard.
Leon is right, you need to define a topic for the default.
However, I'm thinking the issues go deeper. If you are seeing repeated buttons (which we cannot see because you used the attach function and not the camera icon when you posted) my guess is that you are seeing WebHelp load inside WebHelp. And something is screwy with that for sure. The screwy part is likely the reason the page is blank.
You might try replying and using the camera icon to post that second image. That way we will see it immediately and it won't get stuck in a queued status.
When you examine your topics inside the editing environment, do you see lots of little red squares littering the pages?