I created a new organization and copied views/reports into the new org. However, when I try to access the reports with a user in that org, I get an error that the user does not have access to the data. I tried to create a new folder for Data Sources in the Org but when I create a new Adhoc View, the new DS does not appear in the list of DSs. I read through most of info on Data Sources but cannot find anything to specify where DSs must be stored in order to appear in the DS list. How do I make Data Sources available to an Org?
As you've found out, just copying reports is insufficient. You'll have to copy all the resources too.
Instead of copying data sources, try creating a new datasource in your organization. JasperReports Server keeps track of resources by internal ids and copying may not have updated these ids.