
The error is kind of clear, it says a file has an unexpected _thing_ is its content. You could share the line content (and its surroundings) so maybe we can guess what is wrong.
If I have to guess, when you received the "Can't launch SQL error. Or the 500 error" error the script hasn't loaded all files (otherwise you would have received the parse error before getting the "Can't launch SQL error. Or the 500 error" error) and now that that error is "fixed" the script is trying to load a file that has a parse error.
Since line 398 of the official package index.php file doesn't try to load files we can only guess what the problem is.
https://github.com/mybb/mybb/blob/featur...x.php#L398
Please be kind and provide more information.
If I have to guess, when you received the "Can't launch SQL error. Or the 500 error" error the script hasn't loaded all files (otherwise you would have received the parse error before getting the "Can't launch SQL error. Or the 500 error" error) and now that that error is "fixed" the script is trying to load a file that has a parse error.
Since line 398 of the official package index.php file doesn't try to load files we can only guess what the problem is.
https://github.com/mybb/mybb/blob/featur...x.php#L398
Please be kind and provide more information.