j_security_check problema

HTTP Status 400 - Invalid direct reference to form login page

type Status report

message Invalid direct reference to form login page

description The request sent by the client was syntactically incorrect (Invalid direct reference to form login page).
Apache Tomcat/5.5.16

<security-constraint>
		<web-resource-collection>
			<web-resource-name>Locadora</web-resource-name>
			<url-pattern>/seguro/*</url-pattern>
		</web-resource-collection>
		<auth-constraint>
			<role-name>admin</role-name>
		</auth-constraint>
		<user-data-constraint>
		    <transport-guarantee>NONE</transport-guarantee>
		</user-data-constraint>
    </security-constraint>
    
    <!-- Definindo o tipo de login realizado -->
    <login-config>
    	<auth-method>FORM</auth-method>
    	<realm-name>Area protegida</realm-name>
		<form-login-config>
                <form-login-page>/index.jsp</form-login-page>
                <form-error-page>/cadastroFalhou.html</form-error-page>
        </form-login-config>
    </login-config>
    
    <!-- Declarando os tipos de papéis existentes --> 
    <security-role>
       <role-name>admin</role-name>
    </security-role>