It looks like the problem is on your le-pays-de-dabo page so you need to have a look at that page and check if anything is overlapping the menu links. Check you don't have for example duplicate menus or something on top of each other, preventing the click from registering. It's hard to tell the exact problem or how to fix it without seeing the page in Xara. If you still can't figure it out maybe post a xar file with just that page so people can check it out for you.