I have just installed some WordPress plugins that try to create files in the blog directory. They use the get_home_path function, which returns the path of the WordPress installation. Therefore, the files are created in the wrong directory. To fix this problem, I have released an updated version of MultiWP. Unfortunately, this time, you have to modify one line in admin-functions.php to make it work. Detailed installation instructions are included. If you update from MultiWP 1.0, be sure to also update the multiwp.php plugin file. I have also improved the wordpress/wp-config.php file. I encourage you to update that file as well (be sure to adjust the base path in line 11 if needed (see included howto)), but it should work with the old one as well.