Here's the 2 part fix.

Line 56 of dosearch.php has this:
Code
"wordlets" => array("dosearch"),
Change that, to this:
Code
"wordlets" => array("dosearch","island_search"),

Second part. Line 70 has this:

Code
if ($textsearch == "Advanced") {
Change that, to this:
Code
if ($textsearch == $ubbt_lang['ADVANCED_BUTTON']) {