After quite some time, I visited this my blog to apply the most recent WordPress upgrade, the 2.9 release.

After the I finished the upgrade, the front-end rendered fine, while I constantly got an error from with ADMIN site: HTTP 500 error.

In case your site runs on a server hosted by 1&1 too, you have to do two things to get ADMIN running again:

1. Create a php.ini in WP’s root directoy and add this single line of text:

memory=20MB

2. Edit WP’s .htaccess file  and add

AddType x-mapp-php5 .php

as the very first line.