Hi Sam1996 (are you really 10 years old?) and welcome to our forum!
Sounds like you are using a query adapter for your main data source. You might consider querying the sproc into a separate secondary data source and then mapping that into your main data source, but that's a ton of work.
The main data source no doubt has a schema issue with the query results. You'll want to look at the XML returned and see what values are not in compliance with the XML schema. Maybe there's a node that's not repeating that is getting extra XML. Not sure, but this is why the Database Accelerator is a good tool for you - it simplifies the whole process of interacting with the DB by segregating the schemas - forms are roundtripped as XML and shredded out as SQL data for reporting. The SQL relational data is not used to rehydrate XML.
Patrick Halstead
Project Manager at Qdabra