From DVD Architect Pro 5.2 online Help: "Error messages"
"One or more menu links overlap:
This message indicates that a button or text box is overlapping another link. If you're creating a DVD project, you can burn your project with overlapping links, but your disc can be more difficult to navigate: when you highlight one link, the overlapping link may also be highlighted. If you're creating a Blu-ray Disc project, you cannot prepare your project with overlapping menu links; you must fix the issue before proceeding.
Navigate to the page and move the link as necessary. When you preview the page, move the highlight among links until you can see which objects overlap."