BuddyPress.org

Here some things I noticed about your site. You are running two plugins that use js which could interfere with the operation of the wpmu backend media popup. Geopress and Lightbox. Plugins that run js sometimes don’t play nice together. Try disabling those to see if the problem clears up.

Also the bp-events plugin doesn’t seem to be loading it’s css. Looks like the const BP_PLUGIN_URL is not defined. That’s an indication that you are running something less than the current trunk. The bp-events plugin seems to assume that you are running svn trunk bp. BP_PLUGIN_URL is only defined in recent trunk versions of bp.