BuddyPress.org

Whatever is going on it’s not the capabilities.php file that is the issue. What version bp and wpmu are you attempting to install. Install wpmu first and get that to run. If wpmu isn’t operating correctly then bp will not.

1) What version wpmu. Specifically wpmu 2.7 or wpmu 2.7.1 beta?

2) How are you configuring wpmu? subdirectory, or subdomain?

3) Are you installing wpmu in a subdirectory of the document root or in the document root?

4) When does this error occur?

5) Can you create blogs in wpmu and reach them?

6) Does creating new blog posts in each blog work and can you pull them up and view them?

7) Is this shared hosting or on a DV?

Have things been working all along just fine and now this error for no apparent reason?

9) Disable all plugins and try doing whatever it was that lead to this error. Does the same thing happen.

10) Disable buddypress and try doing whatever it was that lead to this error. Does the same thing happen.

We could use some more details.