Can you explain the steps you took to install Flarum originally ? Did you use Composer or the ZIP download ? Did you install any extensions locally? Are you able to run the php flarum info command on XAMPP so we can see details about the forum before the move?
The first problem seemed to be that you crested a config.php with the wrong database prefix. Perhaps it's s case sensitivity issue between Windows and Linux.
The second problem seemed to indicate your database is corrupted. If this error was not present on XAMPP, If suggest deleting the database and re-importing the backup. See if there's any difference.
If you have access to a tool like phpMyAdmin, can you go and check if the column it says does not exist actually does or does not exist ? That participer column is part of the base Flarum installation so it should always be there.
PS: you can share your error logs directly as text in your posts.
