Unable to create / select a fill

[Flashgordon]

Sometimes when working with complex drawings I am unable to fill in an area which looks perfectly enclosed. Even if it wasn't perfectly enclosed, I should be able to use the 'close gaps' option. This doesn't work either. I Have got around the problem by manually painting inside the area but then I get the problem that I can't subsequently select that paint area.
I have checked the connecting points in the shape and there are definitely no gaps. Is this a bug in flash (Version 5) and can anything be done about it?

Thanks

Ansy.