What’s the issue?
On the page in the screenshot, you select the domain for which you want to enable errors, then click Alter PHP Directives. Then you’ll be brought to a page where you can enable errors for that particular site.
I did this and checked the error.
The issue is caused by the fact that the index.php file of your site does not contain valid PHP code. Instead, you just replaced the contents with some WordPress data export file.
But if you want to import an existing website, this is not the way to do it. As you can actually read in the file itself:
<!-- To import this information into a WordPress site follow these steps: -->
<!-- 1. Log in to that site as an administrator. -->
<!-- 2. Go to Tools: Import in the WordPress admin panel. -->
<!-- 3. Install the "WordPress" importer from the list. -->
<!-- 4. Activate & Run Importer. -->
<!-- 5. Upload this file using the form provided on that page. -->
<!-- 6. You will first be asked to map the authors in this export file to users -->
<!-- on the site. For each author, you may choose to map to an -->
<!-- existing user on the site or to create a new user. -->
<!-- 7. WordPress will then import each of the posts, pages, comments, categories, etc. -->
<!-- contained in this file into your site. -->
But before you can do that, you need to restore the original WordPress code. You can do that by replacing the current index.php file of your site with one from a fresh copy of WordPress. The process is pretty similar as we’ve described here, except now it’s very likely to only be a single corrupted file:
After that, you should be able to login and import the data file according to the instructions contained within.
But that’s not the recommended way to migrate a website. This is our recommended method:
As a tip in general: please carefully read instructions. If you get stuck, please consider asking for help instead of making your own assumptions on what to do. And always tell exactly what you are trying to do and what you did, and where you are stuck.
This applied both to information provided by us and by WordPress. All the issues here could have been avoided and fixed by correctly following instructions instead of making assumptions about how things should work (e.g. replacing WordPress core files with backup data or looking for an error message without enabling error messages).