Mass Email Sender ONLY works with Multisite?

I have a single site installation and need a plugin that will allow me to send an email to all my users. I tried Mass Email Sender but it triggers a fatal error when I try to install it. Does this plugin ONLY work with multisite? If so, you should seriously rethink that. I would expect all your plugins to work on both or have 2 versions. I know you guys are working hard and have covered a lot of ground in updating your family of plugins, but that is something that should be a high priority in development. Thanks!