Enhanced stroke

Hi,

I am having problems creating a Flash movie for Flash player 7.

I am using Macromedia Flash 8 Pro in a Mac. I create a simple shape using the circle or rectangle tool, and when I try to publish the movie, I get this error message in the Ouput panel:

WARNING: This movie uses features that are not supported in the Flash 7 player
Scene=Scene 1, layer=Layer 1, frame=1:Enhanced stroke is not supported in this player

Could anyone please help me figuring out why it is doing this?

Thanks a lot