MKACTIVITY prohibits my Mactivity on SVN. I got this error when I tried to commit my “collapsable blogroll” code:

svn: Übertragen fehlgeschlagen (Details folgen):
svn: MKACTIVITY von '/!svn/act/fd9073ea-f545-4631-9eec-86beecf71150': Autorisierung fehlgeschlagen (http://svn.wp-plugins.org)

I googled for it and it seems to be a mac specific problem. You have to delete ~/.subversion. Then you’re able to commit with

svn ci --username yourname --password yourpassword -m "Your message"