WordPress MU

I have just installed WPMU and it seemed to go smoothly with the install but now when I try to login I get the following error:

Warning: Invalid argument supplied for foreach() in /usr/local/psa/home/vhosts/renraz.co.uk/httpdocs/multi/wp-includes/capabilities.php on line 31

Warning: Cannot modify header information - headers already sent by (output started at /usr/local/psa/home/vhosts/renraz.co.uk/httpdocs/multi/wp-includes/capabilities.php:31) in /usr/local/psa/home/vhosts/renraz.co.uk/httpdocs/multi/wp-includes/pluggable.php on line 372

Warning: Cannot modify header information - headers already sent by (output started at /usr/local/psa/home/vhosts/renraz.co.uk/httpdocs/multi/wp-includes/capabilities.php:31) in /usr/local/psa/home/vhosts/renraz.co.uk/httpdocs/multi/wp-includes/pluggable.php on line 373

Warning: Cannot modify header information - headers already sent by (output started at /usr/local/psa/home/vhosts/renraz.co.uk/httpdocs/multi/wp-includes/capabilities.php:31) in /usr/local/psa/home/vhosts/renraz.co.uk/httpdocs/multi/wp-includes/pluggable.php on line 334

I have tried looking in capabilities.php but it is way beyond my own php capabilities :-)

System:
apache: 1.3.33
php: 4.4.2
mysql: 4.1.11

When you say you're logging in, how are we doing so? Is this the admin account? Where within your site are you logging in? Main blog? User's blog? Have you tried creating a user account with blog to see if you get this error?

I'm showing line 31 of wp-includes/capabilities.php to be about the user roles. The codes's been around for four months and no one else has reported an issue. I'm thinking it's an issue with this specific account that you;re using.

It is the main account. The site is up and running and you can set up new accounts and login to them etc.

You can see it here: http://renraz.co.uk/multi/

You are more than welcome to set up an account or whatever as this is just set up as a test for me to learn to understand MU - the real site will go up on another domain name.

Help is greatly appreciated.

Could have something to do with running PHP 4.4.2??

Shouldn't as that's what I'm using.

Really would be nice though if you answered the rest of the questions though.

Ok, haven't had the time to work on this the last few days. Let me try and answer properly.
Yes, it is the admin account. I am logging in to the main blog using the link on the home page (default theme as I haven't been able to change anything yet).
I have tried to create a users account and that seems to be working but only if you use the login page for that specific blog (not sure if that is always the case? I assume not). If I use the user account credentials on the main login page I get the same error.

I do have another Wordpress blog (Not MU) using the same database but I changed the table prefix before running the install so I assume that wouldn't be a problem?

Thanks for the help!

Further info - on the homepage there is a news section and where there should be something about updated blogs I get the same error message:

Warning: Invalid argument supplied for foreach() in /usr/local/psa/home/vhosts/renraz.co.uk/httpdocs/multi/wp-includes/capabilities.php on line 31
test1

This error message is output inside an anchor to the newest blog...

I'm still struggling with this. Is there noone here that have any ideas?

I did a test. At oron.com, same problem. But that Host is not configured. Look instruction, or photomatt.net/2003/10/10/wildcard-dns-and-sub-domains/

i have the same problem with fresh install.
Does anybody know how to solve this problem please ?

please see the problem here : http://tinyurl.com/23f328

(p.s the server is using PHP Version 4.4.7 )if this is the cause of these errors plz let me know

[update]
I deleted wpmu and then uploaded it again ..Still facing the same problem !
I also read the instructions here
http://codex.wordpress.org/FAQ_Troubleshooting#How_do_I_solve_the_Headers_already_sent_warning_problem.3F
and the problem is still exist :(
please help!

[update]
Those errors disappeared when i uploaded the original "wp-config-sample.php" file without alteration!

All of the errors were appearing because i had modified this line :
define('WPLANG', '');
and made it like this :
define('WPLANG', 'ar'); (to accept Arabic charset)

So now my wpmu is working without any problem :D
but it doesnt accept Arabic :(

[update]
I just downloaded "wp-config-sample.php" and altered that line to be ok wit hArabic settings , then uploaded.

Now everything is working ok with Arabic , English and French lol!

SO my advice to all newbies like me is that never ever alter anything in "wp-config-sample.php" before the installation complete :p