Problems installing

I had this blog working but suddenly it has stopped and after login I am getting these messages:

Warning: Invalid argument supplied for foreach() in /home/nimline.com/www/vibe/wp-includes/capabilities.php on line 31

Warning: Cannot modify header information – headers already sent by (output started at /home/nimline.com/www/vibe/wp-includes/capabilities.php:31) in /home/nimline.com/www/vibe/wp-includes/pluggable.php on line 480

Warning: Cannot modify header information – headers already sent by (output started at /home/nimline.com/www/vibe/wp-includes/capabilities.php:31) in /home/nimline.com/www/vibe/wp-includes/pluggable.php on line 481

Warning: Cannot modify header information – headers already sent by (output started at /home/nimline.com/www/vibe/wp-includes/capabilities.php:31) in /home/nimline.com/www/vibe/wp-includes/pluggable.php on line 391

I have re-installed, empied all the tables etc. but after installation I keep getting these messages. Any ideas anyone?

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