If our plugin ( or any other for what it matters ) crashes your website, to have your website up and running again simply use ftp to rename our plugin folder. Our plugin folder is called all-in-on-event-calendar and it's found under wp-content/plugins. Just rename that folder and your website will be up again.
When your site is online again, go to the plugins page and delete the Lite version.
Then go to our website and download the standard version and install it.
If you still have problems, post a question on our support forums.