[Koha] Problem in advanced search

[anastasi at inventati.org]

Hi everybody,
I have installed Koha 10.5 (UNIMARC) in Centos 6.3 here 
http://biblio2.berneri.apiedelibero.net/
If I search for (in the normal search box) "kropotkin" I get the result 
but If I search for  the same word in the advaced search, choosing the 
Library "Biblioteca Circolo Anarchico Berneri", I get no results. I have 
already talked about this problem in irc without finding a solution. 
Unfortunately it seems that there aren't useful logs.
Please, can someone help me?
Thank you in advance,
Gio