When you move, cut, rename, or delete a Data Model, a Sub Template, or a Style Template that is used as a resource for a report, the references to the resource are broken and the report cannot run as expected.
For example, if you have a report that was created with a data model that resides in a folder called My Data Models, and you move the data model to another folder, the report cannot run because the report definition is expecting to find the data model in the My Data Models folder.
If moving a resource object is unavoidable, then you must edit each report that references the object to refer to the object in its new location.