Download attachments for older posts no longer working

Hi there,

Downloading attachments from older posts in easydiscuss is no longer working on my site. If you click to download, it returns a blank page.

Here's an example of the url that's returned after clicking an attachment to download: https://intranet.brainjuicer.com/discussions?controller=attachment&task=getFile&tmpl=component&id=13

Through the backend, it looks as though the attachments have disappeared but I can't re-add them (clicking 'choose file' doesn't do anything). I'm not sure whether it's never been possible to attach files through the backend as this is usually done through the frontend.

Unfortunately I'm not sure when or why this has stopped working. Attachments in new posts work fine but reattaching files to old posts doesn't.

Any ideas what might be happening? Otherwise I'm going to have to recreate hundreds of posts with their attachments from scratch...

Thanks!