wp audio player: File not found

I installed WP Audio Player on my site, theme:Twenty Twelve. I put the files in the folder audio, and the path is verified. But I keep getting the message: File not found. I wonder why? Tried with absolut as well as relativ address. The files are fine directly in the browser. Other posts talk about interference from other players, and there is the inborn (insuitable) audio player. How can I check if this the problem?

http://schousfreelance.dk/energi/biogas