[Error Message] 500 internal server error message after missing index.php

[superstarcrasher]

Hello,

My forums (http://superstarcrasher.com/cblcn/) developed an issue where attempts to click any actual forum links would lead to a "missing index.php" error message. I hadn't done an upgrade in years, but I finally upgraded the forum to 1.822 and it did not resolve the issue. I then decided to deactive an SEO plugin (which is: SEO Links! by Asad Niazi, v. 1.0 Beta 9) I had to see if it was maybe that, which led to to a 500 internal server error. 

How do I fix these issues? Where do I start?

Thank you!

[noyle]

You should check relevant logs such as PHP error log, HTTP server log, etc. for anything that relates to the 500 internal error for detail.