Problem showing files in tree list.

Hello. I’m having problems showing items in tree list.
My files are in wp-content/uploads/filebase/ (there are folders, and inside .pdf etc).
When I go to the page, where this items are listed, the folders open, but the pdf is not showing (no chance to see or download it).

I wait a quick answer. Thanks!

http://ww.wp.xz.cn/extend/plugins/wp-filebase/