Sub Menus / Login

I can't access sub menus when I click on menu. I stay at the menu level and the articles from the section corresponding to the menu item display (blog form). But I can't drill down to sub menu and the the articles from the category corresponding to a sub menu item.

When I add a login form, if I login I jump directly to the sub menu corresponding to the to the first item menu. After login, I can't reach no more the menu, only the first sub menu.

The previous post is about the iPhone template.