Ruby application returning wrong content type

Hi,

I have a customer who is using redmine (a popular Ruby app), but confesses to not knowing much about it's installation. It has apparently worked for a while on our server, and recently stopped working, and now when browsed, returns the correct initial page still, but the content type is httpd/unix-directory to it's just downloading the file.

I restarted the rails app, and apache. I'm no RoR expert, so does anyone know of any reason why our WHM server might have messed up this install?

Ste