An omeka installation I'm doing some development work for seems to have a problem with the advanced search. The keyword search works fine, as does the Collection search. However, it seems like no matter what you do with the "Narrow by Specific fields" options, the search returns all items.
You can try it at http://cdp.coalliance.org/items/advanced-search
From some other posts in the forums, I'm wondering if it's a misconfiguration in the MySQL installation. If anybody has any ideas I'd love to hear them.