Can't upload any media after update

After updating to the latest version I can no longer upload any media (photos, videos etc).

When I click the upload/insert button the Add media files from your computer pop up appears, but no longer shows the drag and drop area and the “select files” button does nothing.

If i try to click the “browser uploader” link, nothing happens as well.

this happens on multiple browsers on all my computers.

what did I break during the update, and how do I fix this?

thank you very much

my site is http://www.TrulySimple.com if that matters

Ben…