syncope on "search results error"

I installed ZenPhoto 1.4.2.3 (PHP 5.3.17 and MySQL 5.1.65) a few months ago and it has been running well, but I'm getting errors with the search function recently. I will search for a term and get back 2 or 3 results pages. The first page is fine, populated with thumbnails that link to images, but when I click on a second or third page of results, the page is blank and I get a "images not found message". I set the Boolean to "and" and refreshed the metadata, but the problem persists. Anything else I could try? Thanks for any advice. I've not had any other problems or error messages.