I don't know if the Events+ plugin has role limitations but came across this:
As a member who is a "Subscriber" I was not able to "Add Map" to an event I was creating.
I changed the role of the member to an "Administrator", "Editor" and "Author" in that order and was able to "Add Map".
I changed member to "Contributor" and "Add Map" did not work.
I am hoping that a "Subscriber" member can "Add Map" because all members registering on site are designated as subscribers.
Also, do not know if this is an Events+ issue but when I am creating a new event as a logged in "Subscriber" member I am able to choose either the administrator (there is only one designated on my site) or as the "Subscriber" member from the drop down "Author" box at bottom of page. This is a bug because only the "Subscriber" member should populate the Author box.