I turned on WP_DEBUG and got a Doc Repo ob_clean() error:
Notice: ob_clean() [ref.outcontrol]: failed to delete buffer. No buffer to delete in /home/user/example.com/wp-content/plugins/document-repository/document-repository.php on line 297
I searched and found this: http://stackoverflow.com/questions/3521612/php-force-an-image-download-from-above-directory-root
I added ob_start(); to line 297, just before ob_clean() in document-repository.php and all's well, no error.
I posted previously about duplicate entries. As it happened, I got a request to make the doc repo admin searchable, so searched, found, and installed the MetaSearchTo plugin, and used Yoast's SEO plugin to assign a focus keyword (the slug) to each doc, worked well, until it didn't. The MetaSearchTo plugin zonked out with the latest WP update, creating the aforementioned duplicate entires. I replaced MetaSearchTo with Relevanssi, works fine. However, it's enough of a work around I figured I'd mention it as a feature request here in case you felt it worth integrating, fwiw.
This has more to do with WooCommerce I think, I'm in discussion with their devs currently, but when WooCommerce is active, it blocks doc repo downloads in IE with a XDomainRequest error. Stop Spammer Registrations does the same thing, though that's more understandable, and easier to deactivate without replacing whole sections of the site. I wanted to post about it here so you know it's happening, and in case you've run into this and know of a fix. I'll update this thread once WooCommerce is through testing.