I am using the latest version of DT Register, 2.5.1, and find that when I use the plugin there are issues with the display of modules.
What happens is that on articles that are tied to events, where the plugin activates, I end up with modules being displayed that should not be displayed. Also, I end up with multiple copies of some modules. Sometimes up to 10 to 20 of them.
When I disable the plugin the article displays fine, with the modules it is supposed to have.
YES, I also have this problem. I am running a module that embeds flash on the homepage inside a user position. The flash module tries to display on the event page where the register links are. When I added another custom HTML module which appears on all pages, I get duplications... like you stated, 1 for every menu item!! The only way I solved this was to hack another custom HTML module that sets styling to disable that module position.
Another issue with the View all Events / Register Now button is that it is allowing me to register for events that are already over!!! Ack!!!
Guys... please download the latest package of DT Regsiter and update the component, module and plugin. You should find your issues to have been resolved. If you have any remaining issue, please log a support ticket with sufficient details so we can check it out.