WordPress version: wordpress-3.4-nl_NL (Dutch)
Disqus WordPress plugin: Stable tag: 2.72
I get a 500 server error when enabling the Disqus plugin.
Theme: my own, but the same problem when changing to twentyeleven.
Disabling the plugin (by changing the plugins folder name since I can't access the Admin) resolves the problem...
It am developing local, but when I had the English WordPress installed Disqus was working fine..