mysql_query("UPDATE customers SET balance = (SELECT SUM(b.balance) FROM trailers AS b WHERE b.customer_id = customers.customer_id)")or die(mysql_error());

The query worked locally using WAMP...but when I upload to providers server...it gives a syntax error:
"You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT SUM(b.balance) FROM trailers AS b WHERE b.customer_id ="

MySQL 4.0.16 running on both. What did I miss?

Thanks for any help!
Chris