Hi Nathan,
Following your description, I did some experiments with AIP2009 but no such dialog came up on my side. Do you use any particular dataset/workflow? If so, I wonder if you can share it so that I can hit the point. Also it's better to let me know the operating system you work on.
One Tip: Inventor 2009 SP1 was just live on the web. Maybe you can patch it and have a try once again if the problem can be solved.
Thanks,
Macro