Been doing some testing here. I found that I had to specify at least CountryCriteriaId to get it to work, but if I specify any of the other fields it fails.
Hopefully there will be a fix for this ASAP as it is vital part of our internal process.
*** Works for this set of fields
AdGroupId
AdGroupName
CampaignId
CampaignName
Clicks
Cost
CountryCriteriaId
Date
*** Fails if I add RegionCriteriaId to the above
*** Fails if I add MostSpecificCriteriaId to the above
*** Fails if I add CityCriteriaId to the above
*** Fails if I add MetroCriteriaId to the above