This access denied message appears as an Internet Explorere dialogue box, and not the SharePoint access denied lightbox that we would normally see. Also, this message appears for some people, and not others.
Ok, so it turns out the solution to my problem was related to sharepoint list permissions. I was trying to trigger a workflow to copy a list item to a new list, and had added the appropriate permissions to the destination list, and not the list that
the workflow was being triggered on. After adjusting the permissions on the source list, my users are no longer receiving this error
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