Argument exception was unhandled by user code

Make sure that dataset contains tables. And first table contains contributorId column. I guess you have multiple tables in in your dataset and contributorId is present in some other table.

 

Put a debugger point and see how many tables you are getting and which table contains contributorId. 

 

Please recheck it. 

 

If it doesn't resolve your problem please provide your sql code and error you are getting.