Unable to load page

1. I've launched the program
2. I chose to load my book collection within a directory. So i put my calibre library directory
3. I've got dozens of items, apparently with a default icon.
4. When i'm clicking on one of them, here's the message :
"Unable to load page

Problem occurred while loading the URL file:///var/tmp/fantasy/epub.html"

5. Neither view changing buttons nor the filter buttons (by author, series) seem to work. Search doesn't work better.

I don't see any button to add a ebook anew to make further tests.