ok. so i enabled fastcgi using htaccess. everything's working great. seems a bit faster. running wp 3.0.1 and bp 2.6.1. doing my usual 4 major browser tests. get to chrome, then the strangest thing.
when logged in, clicking on the buddypress admin bar My Blogs drop down, then selected a blog, then clicking on Dashboard DOWNLOADS the page as a file (rather than taking you to /wp-admin/).
the link says wp-admin. when i type http://subblog.maindomain.com/wp-admin/ into chrome address bar, it also downloads what i think is the wp-admin index file...
i turn off fastcgi, everything's back to normal. ha ha.