I am having the same problem. But my submenu is also behind the text of the page and seems to be centered instead of aligned left.
The crazy thing is I have two identical websites, one is working fine and the other is not. http://www.enjoyrwanda.info is fine http://www.enjoyburundi.info is not.
In both cases I did put this:
‘<?php shailan_dropdown_menu(); ?>’
as the second line in the page.php after the header php.