Call to a member function execute() on boolean in

This may help someone: I was facing same issue. In my case, i have missed to close first prepared statement before executing second prepared statement.

When i have added $select_stmt_type->close(); before executing second prepare statement, it fixed the issue.

mysqli->prepare can also return FALSE (check http://php.net/manual/en/mysqli.prepare.php) if an error occurred. Your problem is that you have INSET instead of INSERT.