We recently ran into a problem when we create a document via the api when the document name is the same. The error we are getting is

"Create Failed: DUPLICATE_DEVELOPER_NAME: This Document Unique Name already exists.  Please choose a unique name. -- DeveloperName"

I thought that specifying the DeveloperName on the document object would be enough, but when I try that, the error I get is

"Create Failed: INVALID_FIELD_FOR_INSERT_UPDATE: Document: bad field names on insert/update call: DeveloperName -- DeveloperName"

This seems a bit contradictory. Any help would be greatly appreciated. Thanks!