I have an issue with "&" (ampersand) in filenames.
When i am on the edit page, the link to the uploaded file does work : http://www.mysite.com/sites/default/files/GT&W.pdf
however when i'm on the view page (like any visitor), it doesnt work : http://www.mysite.com/sites/default/files/GT%2526W.pdf
Looks like this is a bug from the module.
I will try version 6.x-3.4, but i dident see any related bug fix from version 3.3 -> 3.4.