There is no default application to open these plugins so your Mac thinks that MOTU might do!
Control click the plugin file and select "Get info". Look at "Open with:" in the info window.
To prove to yourself that Adobe Flash is working, all you have to do is play a flash file off the internet like the one on my page.
Go to Finder/Go/iDisk/My iDisk/Web/Sites. Open your website folder and create a new folder and name it something like MusicFiles.
Upload your song file(s) to this folder by drag and drop from your desktop or a Finder window.
The URL of this file will be...
http://web.me.com/username/WebsiteName/MusicFiles/NameOfSong.mp3