I was trying to define labels for the content type in a document library. I kept getting the error:
"The label reference, MetaDataFieldName, could not be found"
The column did exist but the error persisted. So I turned off labels, set the auditing values and saved the policy. I then went back into the policy and defined the labels and it worked. Not sure why, but it seems you have to create and save the policy first, then return and add labels.