Newbie Problem 101

Heya… well, as the title kinda suggests, I have a newbie problem which is probably incredibly simple to yos pros… <sighs> But anyways. I’m Zo, pleased to meet you all.

I’m having problems killing shapes I draw in Flash with colour - say I draw a circle with the pencil tool (it’s just an example, I know all about the wonders of the oval tool) and I select a colour, use the Painbucket (K) tool to try and fill it, it won’t. Any idea why this is?