Why can't I embed one drop.io-hosted audio file into another drop?

According to the drop.io FAQ:

How do I embed things in my drop? What things can I embed?

All you have to do embed objects into your drop is to dd a note, click the embed button, paste in the embed code and your done. We currently support media from:

* YouTube
* Vimeo
* Viddler
* Seesmic
* Twitter
* uStream
* Hulu
* Revision 3
* DailyMotion
* Drop.io widget/video/pics/audio

I've tried this, but all that gets displayed is "Discover Simple, Private Sharing at Drop.io"

Help!