Another GEEK question

OK, I know I'm pushing the 'free Windows advice' envelope here, but I
couldn't find anything at all about this on google.

Whenever I open Explorer, I get this popup window called "flash player debug
console" telling me I have a 'security sandbox violation'. Inevitably, it
tells me that my yahoo account was trying to open some javascript banner
(my.yahoo is my default opening page). I can't find out how to get rid of
this bug.

This just began happening this week, and closely correlated to me opening a
site that had song I was teaching my Chemistry kids.
http://www.privatehand.com/flash/elements.html
The site always opened fine (it has a cool Flash Animation on it, check it
out) but one day this week, the author modified his animation. My thought
was that, among the changes,he must have upgraded it to a newer version of
Flash and somehow my computer recognized that when I ran the animation,
which then changed some settings in my computer. But I really have no clue.

I've uninstalled Flash, but that doesn't help. This damn popup screen is a
real pain....do any of you Windoze experts have any advice (other than
defenestration), or leads to where I can go for more clues on how to get rid
of it?

Thanks

--riverman