Around line 75 is the cart logic for checking an empty shopping cart in the EditCartBody.jsp file:
<div class="body-content-div">
<logic:empty property="itemList" name="EditCartForm">
<div class="msg-box"><bean:message key="edit.cart.body.emptycart"/></div>
</logic:empty>
<logic:notEmpty property="itemList" name="EditCartForm">
//Everything else happens here
</div>
</logic:notEmpty>
</html:form>
The nesting is incorrect, so if your cart is empty, you will be missing your closing tag for the 'body-content-div'.
The two fixes for this are adding a closing </div> tag to the <logic:empty> section:
<div class="body-content-div">
<logic:empty property="itemList" name="EditCartForm">
<div class="msg-box"><bean:message key="edit.cart.body.emptycart"/></div>
</div>
</logic:empty>
<logic:notEmpty property="itemList" name="EditCartForm">
//Everything else happens here
</div>
</logic:notEmpty>
</html:form>
OR taking the last </div> in the <logic:notEmpty> tag and putting it just outside the tag:
<div class="body-content-div">
<logic:empty property="itemList" name="EditCartForm">
<div class="msg-box"><bean:message key="edit.cart.body.emptycart"/></div>
</div>
</logic:empty>
<logic:notEmpty property="itemList" name="EditCartForm">
//Everything else happens here
</logic:notEmpty>
</div>
</html:form>
That should help fix any layout issues you may be having with this page.