One of my WordPress 2.8.6 sites recently became unable to load, producing only 500 "Internal Server Error".
I was able to reach wp-admin and so disabled all plugins then turned them back on one-by-one. I was eventually able to track the problem to WP Comment Remix 1.4.4. When it's enabled, the above error occurs; when it's disabled, the site loads fine, every time.
Shame -- seems like a nice plugin. Anyone else experience this issue?