Friday, August 10, 2012

Report item expressions can only refer to fields within the current dataset scope or, if inside an aggregate, the specified dataset scope.

Use the following list to help determine the cause of the error:
When a report has more than one dataset, an aggregate expression in a text box on the report body must specify a scope parameter. For example, =First(Fields!FieldName.Value, "DataSet1").
To specify a scope parameter, provide the name of a dataset, data region, or group that is in scope for the report item. For more information, see Understanding Expression Scope for Totals, Aggregates, and Built-in Collections (Report Builder 3.0 and SSRS) and Expression Reference (Report Builder 3.0 and SSRS).
Names of objects must be greater than 0 and less than or equal to 256 characters.

The length of object identifiers in a report definition is restricted to 256 characters. Identifiers must be case-sensitive and CLS-compliant. Names must begin with a letter, consist of letters, numbers, or an underscore (_), and have no spaces. For example, text box names or data region names must comply with these guidelines.
To change the name of an object, in the toolbar of the Properties pane, select the item in the drop-down list, scroll to Name and enter a valid object name.