[Plugin: Advertising Manager] Ad won't show up?

I want to put 2 ads at the end of every post and there created in AM: bottompost250 and bottompostright. When I insert the code into my single.php file, I enter this:

<?php advman_ad('bottompost250'); ?><?php advman_ad('bottompostright'); ?>

It only shows bottompost250, I don’t know not the other one? Help me please