Ohhhh, that’s it! I didnt see the link on the right site for site-wide activation in the plugins menu. Thx Andrea for your help!
Oh, btw. I’m using this code, but in the header.php may that be the problem?
if(function_exists('bcn_display'))
bcn_display();
It doesn’t work for me (WPMU 2.9.1) is there a tutorial how to use the mu-plugins folder?
I placed the Breadcrumb NavXT in it, but it didn’t work (or do I have to activate it somewhere?).