I've found this isn't widely know, but when creating a report from an XML schema (that is to be populated from a DataSet) you can not have the option "Save Data with Report" checked. You'll see it under the File menu right below the save command. As long as there is data in the report, it ill not refresh. I'm not for sure if you have to re-create from scratch, or if you can just uncheck that and re-save. Hope that helps.

Thanks,
Danny