i can't log in as an admin since 3.5 upgrade

we-use.com & footballforward.com

Hi all and thank you in advance for your help.
I get the following errors when i try to log into the admin part of my sites.

Warning: Missing argument 2 for wpdb::prepare(), called in /home/iain2474/public_html/wp-content/plugins/buddypress/bp-core/bp-core-functions.php on line 143 and defined in /home/iain2474/public_html/wp-includes/wp-db.php on line 990

Warning: Missing argument 2 for wpdb::prepare(), called in /home/iain2474/public_html/wp-content/plugins/buddypress/bp-core/bp-core-functions.php on line 1005 and defined in /home/iain2474/public_html/wp-includes/wp-db.php on line 990

Warning: Cannot modify header information – headers already sent by (output started at /home/iain2474/public_html/wp-includes/wp-db.php:990) in /home/iain2474/public_html/wp-login.php on line 368

Warning: Cannot modify header information – headers already sent by (output started at /home/iain2474/public_html/wp-includes/wp-db.php:990) in /home/iain2474/public_html/wp-login.php on line 380

Warning: Cannot modify header information – headers already sent by (output started at /home/iain2474/public_html/wp-includes/wp-db.php:990) in /home/iain2474/public_html/wp-includes/pluggable.php on line 680

Warning: Cannot modify header information – headers already sent by (output started at /home/iain2474/public_html/wp-includes/wp-db.php:990) in /home/iain2474/public_html/wp-includes/pluggable.php on line 681

Warning: Cannot modify header information – headers already sent by (output started at /home/iain2474/public_html/wp-includes/wp-db.php:990) in /home/iain2474/public_html/wp-includes/pluggable.php on line 682

Warning: Cannot modify header information – headers already sent by (output started at /home/iain2474/public_html/wp-includes/wp-db.php:990) in /home/iain2474/public_html/wp-includes/pluggable.php on line 876

Or when i simply view either site, the sites launch but with the errors below stated across the top.

Warning: Missing argument 2 for wpdb::prepare(), called in /home/iain2474/public_html/footballforward.com/wp-content/plugins/buddypress/bp-core/bp-core-functions.php on line 143 and defined in /home/iain2474/public_html/footballforward.com/wp-includes/wp-db.php on line 990

Warning: Missing argument 2 for wpdb::prepare(), called in /home/iain2474/public_html/footballforward.com/wp-content/plugins/buddypress/bp-core/bp-core-functions.php on line 1005 and defined in /home/iain2474/public_html/footballforward.com/wp-includes/wp-db.php on line 990