Background of the issue:
After going live the WP backend is not working anymore. I have to rename the WPML plugin folder to get access, otherwise I get a fatal error...
I was able to fix the error in the copy of your website. It seems there were corrupt entries in the Database.
Please make a full website backup and follow these steps:
1. Disable all plugins;
2. Change to a default theme;
3. Install and activate WPML from scratch (you should see an error, like before);
4. Log in to your DB Adminer and run the following query:
DELETE FROM wp_options
WHERE option_name LIKE '_wpml_%'
OR option_name LIKE 'icl_%';
Please note that the prefix "wp_" might be different in your specific installation, so please replace it if necessary. That should reset the WPML options and make it work 🙂 Let me know how it goes or if that's too advanced for you.
I checked further, and the same happened here. It's also not working in my copy. I've sent your ticket to our development team, so they can take a better look into it and find a solution. I'll be back as soon as I hear from them. Thanks for your patience.