Security Risk

One or more of the Nucleus installation files are still present on the webserver, or are writable.

You should remove these files or change their permissions to ensure security. Here are the files that were found by Nucleus

If you don't want to see this error message again, without solving the problem, set $CONF['alertOnSecurityRisk'] in globalfunctions.php to 0, or do this at the end of config.php.