Inserted media plays wrong video/audio – very strange

Hey there y’all. I’ve been having problems with inserting audio and video and getting a different file (one that isn’t even on my computer) as playback. For instance: http://tinyurl.com/njzhu2b is a post where I embedded a 26 second clip of a song of mine in milkdrop. The file that is playing back is a trailer for Big Buck Bunny, which isn’t even on my computer. Yesterday I had a hell of a time uploading an audio file that then played back some song I’ve never heard. I had to reencode the audio file, upload, and THEN it played back correctly.

Any gurus have a clue what might be happening?