Accessing dashboard difficulties

When accessing the dashboard, I get this message after logging in:

Warning: Missing argument 2 for wpdb::prepare(), called in /home/jancan/public_html/twosmartchicks.com/wp-content/plugins/wp-squeeze-pro/includes/pluginlib.php(1) : eval()’d code(1) : eval()’d code(1) : eval()’d code on line 55 and defined in /home/jancan/public_html/twosmartchicks.com/wp-includes/wp-db.php on line 990

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

Consequently, neither I nor my colleague can access the dashboard. All help is appreciated.