one of the errors that we are seeing if the if a field is set as a reference field and it is not fully configured to the module it references, the export is failing.
removing the field caused other issues on the export especially if the field is used on pages. We had to go and add the relation or change the field type to text. It was difficult to figure out what the actual field that is causing issue.
That series of events sounds about right; something similar was also encountered by someone else quite recently.
We are planning on general improvements to our error reporting so expect some improvements in future versions.