It looks like you may be truncating the error message. The full error is as follows:
<reportDownloadError>
<ApiError>
<type>ReportDefinitionError.INVALID_FIELD_NAME_FOR_REPORT</type>
<trigger>Cannot select a combination of ConversionTrackerId and ActiveViewCpm,ActiveViewCtr,ActiveViewImpressions,ActiveViewMeasurability,ActiveViewMeasurableCost,ActiveViewMeasurableImpressions,ActiveViewViewability,AverageCost,AverageCpc,AverageCpe,AverageCpm,AverageCpv,AveragePageviews,AveragePosition,AverageTimeOnSite,BounceRate,ClickAssistedConversionValue,ClickAssistedConversions,ClickAssistedConversionsOverLastClickConversions,Clicks,Cost,Ctr,EngagementRate,Engagements,GmailForwards,GmailSaves,GmailSecondaryClicks,ImpressionAssistedConversionValue,ImpressionAssistedConversions,ImpressionAssistedConversionsOverLastClickConversions,Impressions,InteractionRate,InteractionTypes,Interactions,PercentNewVisitors,SearchExactMatchImpressionShare,SearchImpressionShare,SearchRankLostImpressionShare,VideoQuartile100Rate,VideoQuartile25Rate,VideoQuartile50Rate,VideoQuartile75Rate,VideoViewRate,VideoViews</trigger>
<fieldPath>ConversionTrackerId</fieldPath>
</ApiError>
</reportDownloadError>
That being said, I don't see any of the fields you are selecting in the full list either. I'll follow up with the reporting team and get back to you.
Thanks,
Josh, AdWords API Team