Warning: mysqli_real_escape_string

Dear sir

When I active role scoper for other user, and they publish in their accounts I get the following error.. How do i Solve the problem. Ive beeing trying to deactivate, elimnate and reaload Role Scoper doing according to the instructions, but again appears;

Warning: mysqli_real_escape_string() expects parameter 2 to be string, array given in /home2/maucozzi/public_html/wp-includes/wp-db.php on line 1171

Warning: Cannot modify header information – headers already sent by (output started at /home2/maucozzi/public_html/wp-includes/wp-db.php:1171) in /home2/maucozzi/public_html/wp-admin/post.php on line 197

Warning: Cannot modify header information – headers already sent by (output started at /home2/maucozzi/public_html/wp-includes/wp-db.php:1171) in /home2/maucozzi/public_html/wp-includes/pluggable.php on line 1179