This is a fresh install of wpmu on a server that hosts two other WP sites. All is up and running, but when I add a new user via the Users>Add New link, I am able to complete the name and email address, hit submit, and user-new.php never reloads - just a blank screen. (Windows FF and IE say the server gave a ZeroSizedReply error and Squid got no data... I really don't know what that means. Mac FF just goes to blank screen and Mac Safari says the server dropped the connection).
In any event, the user is not created. However, I can add new users via the Site Admin>Users page. But I want the blog admins to be able to add users.
And I want people to be able to register themselves - in that case, same problem as above - wp-signup.php fails to reload, and the creation fails.
I have followed installation pretty thoroughly - php is up to date with 128 mb memory limit, it's a fresh database, etc.
Any pointers?