Is Flash squawking at you because it can’t understand the audio file you are importing?  Try running the file through Audacity and exporting as a standard mp3 or a wav file.  Flash is picky when it comes to some of those audio file types.  iTunes is using m4a and some other types which Flash won’t accept.  Audacity will give you the option to save the file back out as an mp3.  Try it out: Audacity for Mac or Audacity for Windows

BTW you will also need the LAME MP3 encoder. – http://audacity.sourceforge.net/help/faq?s=install&item=lame-mp3