Error 500 means a general server (maybe configuration) error.
So either the server is misconfigured (1&1 servers are usually fine), so the problem might be in your ".htaccess" file or your server has not enough CPU power to complete a script.
When you have the cheapest package of 1&1 there are usually thousands of people on the same server, so maybe it is a little bit overloaded.
You can try to remove the template folder from the installation package. Don't forget to remove the corresponding lines from the XML file. So Joomla installer needs lots of less CPU power to install the component.
When you have installed the component, ftp the missing templates to \components\com_uddeim\templates.
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