Is it really piCal 0.76?
piCal_xoops.php in 0.76 should be ...
// XOOPS Search module
$showcontext = empty( $_GET['showcontext'] ) ? 0 : 1 ;
$select4con = $showcontext ? "description" : "'' AS description" ;
Thus, $event->description should not be empty property.
Though it is an issue of an incompatibility between MySQL versions.