It's not meant to be funny...
We all know that its not meant to be funny. So why bother stating its not?
Aaaaanyways, getting back to topic:
The reason is that you added the WHOLE song, instead, you should probably fade it out somewhere (time how long it takes a very slow reader to finish reading it, then fade the song out at the end, IF you have music editing software, if not, then):
Lower the sound quality.
Simple as that, really, if you lower the quality = less kbps (kilobytes per second), therefore reducing the size of the file. I reccomend either using the compressor within Flash MX or an external one, which tends to work better, because it formats the music BEFORE it goes into flash, making your computer do alot less work. (That is, if you want a happy computer)
And one last thing: Create a box behind the letters in your quiz, it tends to get a bit hard clicking the exact letter, expecially for people who have higher resolutions on their computers.
Hope you create some more things like this, though.