Does not open any files at all!

Dear developer,
I have a problem with a BookReader last week or so. It does not open any book it opened before. The library shelf is working, but klicking on book gives nothing. Same is from Finder - BookReader remains silent. Reinstalling and cleaning Library folder does not help.
Regards,
A K

P.S. Problem is solved by upgrading the system to 10.8 (Mountain Lion)

A K

Alex von Aachen about BookReader, v3.9