FIND:

 NOTE --- This is a partial match, the whole line on a fresh installation looks like this:
	$search_img = '<a href="' . $temp_url . '"><img src="' . $images['icon_search'] . '" alt="' . $lang['Search_user_posts'] . '" title="' . sprintf($lang['Search_user_posts'], $profiledata['username']) . '" border="0" /></a>';

$search_img = '<a href="'

IN-LINE FIND:

. $lang['Search_user_posts']

IN-LINE REPLACE WITH:

. sprintf($lang['Search_user_posts'], $profiledata['username'])