Is this a flash bug?

Hey guys, I was wondering if you could clear something up for me…

I’ve ran into a strange bug related to Button Symbols in Flash Player 9/IE.
Whenever a Button Symbol is instantiated as a MovieClip instance, i get an IE error screen when testing with Flash Player 9. That doesn’t happen in any other major release of the player.

Have any of you ever heard about that?

An image of the error screen is attached below.