For the first of those, it’s possible that the uploaded file is malformed, but in the second, I’m pulling straight from the file; I also tried with the namespace URI that worked with another vocab of the OTG project, https://onthesegrounds.org/vocab#, but that didn’t work for this file.
The OTGEvents Vocabulary is the main vocabulary that includes the properties and classes for making resource templates.
The OTG Event Types vocabulary is a controlled vocabulary, that as John suggested, includes only collections of concepts, so doesn’t have any useful stuff for making templates or items. Though we haven’t done it yet, we’ll serve the contents of that controlled vocabulary as a set of items in an item set so that individual projects using the model can point to those URIs in their Custom Vocab module, once Jim Safley is comfortable merging this branch: https://github.com/omeka-s-modules/CustomVocab/tree/experimental-uri-type That will allow us to fully define and version the terms, without having to spin up a sparql endpoint to serve them.
So, for now, the OTGEvent Types document that you were trying to import is a good reference for the term definitions, but isn’t really functional in the context of Omeka S.