or maybe in response to another config option
why?
because if swf layers contain actionscript events, they don't fire because of overlaying layer.
I think what's happening is that the layer containing GeoRSS annotations, though invisible, is covering your swf layer and blocking any tool tip actions.
One option would be to turn off the GeoRSS layer completely, if there is no feed .. is that a possibility for you?
When I looked directly at the underlying swf, the tool tips were very small, only readable on magnification. Just a observation.
There is a limited amount of styling supported in worldKit. GeoRSS lines can be set to a thickness and color. More styling, as you are using, may be possible in Flash 9 Player, haven't checked.