mod_rewrite must be enabled and make sure your .htaccess is configured properly. It should have the "AllowOverride all" directive and "Options +FollowSymlinks", you can add this in your .htaccess if its not already added.
Here's a little on the file permissions,
All directories should be 755 or 750.
All files should be 644 or 640. Exception: system/tastyigniter/config/database.php and system/tastyigniter/config/config.php should be 440 or 400 to prevent other users on the server from reading it.
I'd suggest uploading a fresh copy and making sure nothing has been added to your database, then clear your browser cache to try the setup process again.