Middle Level of 3 level navigation is not being displayed in the breadcrumb nav

Hi there, I have a 3 Level Navigation in my website. The breadcrumb navigation is not functioning propperly. While it is there, it leaves out the middle level of the 3 Levels. For example, the breadcrumb Navi should be: Main/Second Level/Third Level But it is: Main/Third Level Why is the 2nd Level not being displayed? Can anyone help? Thanks a lot! Dirk