[Plugin: Audio Player] File Not Found Error in Firefox

I installed Audio Player on my WordPress blog a few days ago and all worked fine.

Added a new post with a new playlist today and when I tested it (using Firefox 4) I get a “File not found” error.

So I went back to one of the posts (that was working yesterday) and tried it and again and got a “File not found error” I tried skipping to the next track and again “File not found”

I then opened the pages in Safari and the Audio Player worked for both of them.

Apart from clearing my Firefox Cache to see if that solved the problem I’ve done nothing to the browser.

I’ve tried deactivating all other plugins and that didn’t help (and it was working yesterday with all plugins active on the same version of Firefox).

I also tried unchecking the setup options around endocding mp3’s and removing enclosures with no success.

I can’t for the life of me work out what has made it stop working in Firefox.

Can anyone help me resolve this?