mysql_real_escape_string() [function.mysql-real-escape-string] is preventing server connection

mysql_real_escape_string() [function.mysql-real-escape-string] is
preventing server connection

Can someone explain why am getting this error when am setting up a new
website? and how to solve it Warning: mysql_real_escape_string()
[function.mysql-real-escape-string]: A link to the server could not be
established in /home/sitename/public_html/cms/cms/admin/report.php on line
14
Line 14:
$report = mysql_real_escape_string( $report );