ConcurrentModificationException when using tag

i am using Struts 1.1b2 with tiles on BES 5.0.2(tomcat 4.0.1). i ve got the following form: public final class fw_MenuItemAdminForm extends ActionForm { private List parmsAL = new FastArrayList(); private Collection parms = col1.lazyList(parmsAL, fw_MenuItemParmVO.class); public v

ConcurrentModificationException

i am using Struts 1.1b2 with tiles on BES 5.0.2(tomcat 4.0.1). i ve got the following form: public final class fw_MenuItemAdminForm extends ActionForm { private List parmsAL = new FastArrayList(); private Collection parms = col1.lazyList(parmsAL, fw_MenuItemParmVO.class); public v