W3 Total Cache and IIS7 not doing much [closed]

After more investigation last night, I discovered the problem lay in a malformed PHP file within my very simple child theme.

The child theme was just a stylesheet and a PHP file, so it wasn’t difficult to determine where the problem lay within the theme. A quick look at the PHP showed that it included just <?php?>. I deleted the file and now everything is working again.

error code: 523