uh oh

I can't get to my modules. This is the message that comes up:

Fatal error: Only variables can be passed by reference in /home/content/m/a/r/markcissi/html/sites/all/modules/admin_menu/admin_menu.inc on line 536

I have no idea.......... 536 is in this area. Any help is greatly appreciated.

// Make sure everything is rebuilt, basically a combination of the calls
// from system_modules() and system_modules_submit().
drupal_rebuild_theme_registry();
menu_rebuild();
cache_clear_all('schema', 'cache');
cache_clear_all();
drupal_clear_css_cache();

Mark