WordPress MU

I had used a plug-in called Registered Only with a WPMU download a couple of weeks ago, but with the latest download I get an error message:

Warning: Cannot modify header information - headers already sent by (output started at /home/myblog/public_html/wp-inst/wp-content/themes/default/header.php:5) in /home/myblog/public_html/wp-inst/wp-content/mu-plugins/registered_only.php on line 63

I've been able to relate simlar errors to whitespace at the beginning or end one of the files mentioned but this time I can't find it.

Any suggestions where to look? I'm a little confused by the :5 after header.php.

the plugin is trying to send header information but they have already been sent by header.php

I would just modify the plugin.

Thanks Andrew for your quick response.

And excuse my limited knowledge - but modify the plugin in what way? Maybe I'm wrong, but I think the whole idea of the plugin is that it is first. Its purpose is to cause registered users to login prior to viewing the blog.

send me the plugin and i'll see if I can see what is causing the problem

andrew AT idtstudios DOT com