Issue can be reproduced on SOME documents, not on all of them.

Ways to reproduce:

1. Click "Upload new version" on a document in the doclib or on the document page (https://beecon.orderofthebee.org/share/page/site/speakers/document-details?nodeRef=workspace://SpacesStore/f9a654f4-718a-4370-94da-8caed7c9281f in my case, the same I had with presentation templates).
2. Select a file
3. What for the uploading to 100%, then see "Error"
   
   

Trace in the log:
http://pastebin.com/in9GgbeX

Solution: delete file and create the new one with the same name (but it drops the history :( )