LukeyBoy is right and I would like to expand on what he said. When sending information via a web server the server has to know what kind of content is being sent and verifies that the outgoing content has the correct header on it. In the case of static .htm(l) it adds the correct header for you since it has the correct mime mapping and the content is not being processed by a forgein handler. So adding the line that LukeyBoy specified tells apache that the content is HTML and should solve your Internal Server Error problem.