Some users have seen installations where the JEvents menu item is not visible in the backend of Joomla. If this occurs you could try this script - upload to the root of your installation, make sure you are logged in to the backend of your site as the root super user and then run it as http://www.YOURDOMAIN.com/cleanInstall.php
. Hopefully this will restore your missing menu item.
If you get other errors during install you could try running the script as http://www.YOURDOMAIN.com/cleanInstall.php?cleanup=1
, this will remove some database references to JEvents in the extensions, assets and menu - you could then try re-installing.