I think that what you could do is have an if statement that would asign a variable. You would then send that variable to a .txt file on a PHP server. Then in the movie you can have a loadVariablesNum function, and then a final if statement to determine which frame to go to.
unfortunately this solution reports the movie's url but not that of the html page.
In plain words: if you put a cartoon on your site and somebody wants to steal it, the code would simply force the bad webmaster to link to the movie on your server and thereby steal your bandwidth too.
Some hosts (e.g. geocities) have a technique in place that prevents linking to your images from an outside html page - maybe your host can offer the same on request
for %20: if this is sort of a menu that should know where it is, you could use
<embed src="movie.swf?page=cow" ....> or similar in the html pages.