I use the easy fancybox plugin on several of my blogs and never have had any problems with the plugin. I already have read the http://wordpress.org/plugins/easy-fancybox/other_notes/ section and checked potential conflicts or issues but could not solve the problem.
I tried to use another fancybox or lightbox plugin but there seems to be a general problem with my theme or my WordPress install.
I also tried to deactivate all other plugins in order to check if there is a conflict but even when only the fancybox plugin is activated the problem still exists.
Does anybody have an idea? You can find my blog on http://suedafrika-news.de and a gallery on http://suedafrika-news.de/suedafrika-bilder/kapstadt-von-oben/
Also interesting: If I browse to http://suedafrika-news.de/wp-content/plugins/easy-fancybox/fancybox/jquery.fancybox-1.3.5.js I get a 500 error message.
Thanks in advance!