That's an Apache error message related to Server Side Includes. See the following: http://httpd.apache.org/docs/2.0/howto/ssi.html#config.

One key to solving problems is understanding the error messages. Knowing where the error messages are coming from is the first step in that regard. I happen to know Perl won't ever create that message. If we rule out Perl that leaves dependencies, and in this case the dependency happens to be Apache. To be quite honest, I wouldn't have known that it's an Apache message except for typing '"an error occurred while processing this directive"' into my Google search box and reading a few of the links.