Howdy pagan11460,
The events created by our plugin are just standard WP Custom Post Types. It sounds like this plugin is likely just replacing the standard WP Comment Area with is own version. That being the case you should be able to selectively hide it by going into an event, clicking edit, and then unchecking the box “Allow comments.” under the “Discussion” heading. However, Vivacity has said that this feature is still in development. Once they add that ability you should be good to go. In the mean time their plugin simply does not work with WP Posts very well, which is simply going to be a problem with any plugin that implements them (most large plugins do, ours included).
Does that all make sense? I wish I had some better options for you, but sometimes two plugins just can not work together. On the bright side it looks like they will soon. Please let me know if that answer your questions, or if there is anything else. Cheers!
– Brook