Graphics disappearing when published

Some of the graphical elements in my movies are disappearing when published.

To demonstrate what I mean, here is a screenshot of the my stage:

And here is a screenshot of the same movie when previewed (via: Ctrl+Enter):

Which as you can see, appears as it should. However, when the movie is published, the orange circle disappears:

I am experiencing similar effects on other files. I really am at a loss to explain this; is it a bug, or am I missing something? Thanks for any information that can be shed on this.