Ozh

// Original, doesn't work
$olt_checklist_callback = create_function('$base_url', // Version specific init callback
    'include_once("'.dirname(__FILE__).'/olt-checklist.php");'.
    '$js_url  = $base_url . "/olt-checklist.js";'.
    '$css_url = $base_url . "/olt-checklist.css";'.
    'wp_enqueue_script("olt-checklist",$js_url,array("jquery","jquery-ui-tabs"));'.
    'wp_enqueue_style("olt-checklist",$css_url);'
);

// Fixed, works
$olt_checklist_callback = create_function('$base_url', // Version specific init callback
    'require_once(dirname(__FILE__)."/olt-checklist.php");'.
    '$js_url  = $base_url . "/olt-checklist.js";'.
    '$css_url = $base_url . "/olt-checklist.css";'.
    'wp_enqueue_script("olt-checklist",$js_url,array("jquery","jquery-ui-tabs"));'.
    'wp_enqueue_style("olt-checklist",$css_url);'
);

/*
the only change is that __FILE__ is computed at runtime
*/