Nginx, wordpress mu, Buddypress

Hi

I am hopping that some one can help. I have setup a wordpress mu site with buddypress. The server runs Nginx, varnish cache and memcached. I seem to have problems getting the right rewrite for that setup, I am hoping that someone can help me, as I am having problems with loggin in to buddypress. the site is setup optimizenet.co

I am hopping that some one can help or had this problem before. Also the site is running wp super cache plugin.

if you need any further information please let me know. I am hoping to find a solution which make sure that all the wpmudev plugins will work on this setup

thanks in advance

Karsten