Note: This problem happens with a Shared hosting server using Nginx.

I recently launched a website using the latest version of Drupal 7.24. After launching, I went to the Admin page at sitename.com/admin/config/development/performance and checked the box to Aggregate and Compress CSS files. All my site's CSS styling promptly disappeared. So, of course, I disabled this checkbox.

Then I checked the box to Aggregate Javascript files and my Admin Menu toolbar promptly disappeared.

I don't know what's causing this problem. Could it be the new .htaccess files that are included with the new Drupal 7.24? I understand that the new .htaccess files in the sites/default/files/css and /tmp directories is helpful to prevent hacking. 

Anyone else have problems with CSS styling disappearing?