exception when calling component security (app-hoj)

hi keel-users

i'm in slow progress of going through the hands-on-tutorial and looked 
onto the next error - this time while trying to call the keel-function 
to giving access permissions to a component
--> keel-menu, security admin, component security

result: error 500

org.apache.jasper.JasperException: Cannot find bean header in any scope 
at 
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:254)

it seems to me that it tries to find a bean called header, and the bean 
isn't present?!?

thanks for helping a newbie
stefan