I have a couple of problems with my new installations. I am using timeline but it should be a backend thing (2k11).
User group settings not displaying under (base path)/serendipity_admin.php?serendipity[adminModule]=groups&serendipity[adminAction]=edit&serendipity[group]=1
User groups can be created, but if I try to edit them, I come to an empty page with some truncated code below:
Also, authors are neither displayed in the Extended Properties pull-down for entries (where you can assign other users as admin). Nor by the serendipity_plugin_authors plugin.
htaccess should be fine, categories, archives, user's articles lists do display correctly.