Hmmmm. I was playing around with this on your site and got the same problem you describe. So I tried with my site (that uses a custom theme) and didn't see any issue. So I flipped over to the zenPage theme. Searching for "mountain" got me two hits that displayed. Searching (within the search) for "the" spit out this...
Quote:Notice: Undefined index: albumid in /path/to/my/site/zp-core/class-search.php on line 1408
Fatal error: MySql Error: ( SELECT folder,`show` FROM `[prefix]albums` WHERE id = ) failed. MySql returned the error You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1 in /path/to/my/site/zp-core/functions-db-MySQL.php on line 59
So I jumped back to my normal theme and tried the same searches. No problems.
From the times the search fails and gives the error this can be found in my php error.log
Quote:[23-Dec-2012 11:01:09 UTC] PHP Notice: Undefined index: albumid in /path/to/my/site/zp-core/class-search.php on line 1408
Maybe it will set you on the right track.