Try:
<?php wp_nav_menu(array('theme_location' => 'footermenu')); ?>
<?php wp_nav_menu(array('theme_location' => 'topmenu')); ?>
See http://codex.wordpress.org/Function_Reference/wp_nav_menu
Try:
<?php wp_nav_menu(array('theme_location' => 'footermenu')); ?>
<?php wp_nav_menu(array('theme_location' => 'topmenu')); ?>
See http://codex.wordpress.org/Function_Reference/wp_nav_menu