BuddyPress.org

I’m having a problem with BP elements of my site. I can successfully see blog posts and home page, and all pages load something, but the BP pages e.g. activity, members etc only load with “Edit” or “edit this page” depending on which theme it’s with. I’ve tried with Custom community, BP default, Fanwood. Same problem exists regardless of theme. When events manager is activated, the events page says “Page not found”.
I’ve tried to change permalinks settings to custom setting:
`%year%/%monthnum%/%day%/%postname%/`
and i’ve tried the other options with day and name, month and name. When i change to the custom setting above, the pages bring up a 404 error, then when it returns to the index.php/…….. permalink, the pages aren’t working properly.
I’m using latest stable versions of WP and BP, as well as a few plugins, e.g. events manager, activity plus. i’ve deactivated all except BP and problem still exists.

Incidentally, the themes page shows that twentyeleven and twentyten themes are installed but stylesheets are missing. It might have nothing to do with it but I just thought it’s worth mentioning.

Any help will be greatly appreciated as it’s driving me up the wall. I’ve already abandoned transferring a local site and started from scratch after so many issues!

Thanks.