Re: internal server error after activating bp
Worrying about HD space is not relevant at this stage. Although the HD space is an issue once things are working, I was under the impression that you could not even get WP with BP working, that you kept receiving a Error 500. If this is the case, the allocated HD space is a moot point at this time.
Are you still having Error 500 issues? If so, that is where we need to be focusing the attention, unless you are planning on switching to a different host. Please read the threads that I linked to above. Is your site running under PHP 4 or PHP 5? Also, as @hnla states, there can be other issues with PHP memory limits.
Finally, I am a little concerned that you have manually edited your .htaccess file. If you’ve deactivated and uninstalled all plugins, then the . htaccess file that comes with WP should work fine. Is WordPress working fine by itself once you’ve distilled your WP install down to the lowest common denominator as I detailed in my first post above?
Let’s get WP working first and worry about BP later.