Hi pb36,
I didn’t find any jQuery error of JA Tabs plugin on your website. The main reason is that the menu items (Videos, Photos, Communauté) are being assigned to JA_Magz_No Sidebar layout which doesn’t contain the “sidebar-2” position inside. That is why the ja_tabs modules disappear on this menu item page.
While the New Posts menu item is being assigned to Default layout, so the ja_tabs modules are displaying finely now. The simple solution is assigning the JA_Magz_Default style to the menu items you want to display the sidebar. See this: