[flemmingbjerke]

Thank you, it turned out to be the plugin bp-tinymce that made the problems. The activity/post/ issue was a haphazard.

wordpress: 3.1.2
buddypress: 1.2.8

[flemmingbjerke]

When an activity update is posted, the function bp_activity_post_form_action in wp-content/plugins/buddypress/bp-activity/bp-activity-templatetags.php is called. This function sends defines:

function bp_get_activity_post_form_action() {
return apply_filters( ‘bp_get_activity_post_form_action’, site_url( BP_ACTIVITY_SLUG . ‘/post’ ) );

BP_ACTIVITY_SLUG is just the url of the activity (http://example.com/activity). To this url I added /post, and I tried it in the browser. I got the extremely informative error: “Are you sure you want to do this?” Now, I guessed, it would work without the /post-ending … and it did. (I had deactivated a number of plugins, but now they are activated again).