.ogg file upload creates a 404

Hi,

When I upload a .ogg file (1.45Mo) in the media library that is playable in Firefox, I have no error message and it appears in my media library. Yet when I check the path to the file (e.g http://actu.etoilecasting.com/ec_actu/uploads/2013/08/10620_329983.ogg) I get a 404 error.

Does anyone have any idea of what may go wrong?

Thanks in advance,
D.