I created a typed data set by using Add New Item.

Then I add a matrix to a report (rdlc). I set the Dataset name for the matrix and when I try to build it says:

Error 1 The matrx ‘matrx1’ is in the report body but the report has no data set. Data regions are not allowed in reports without datasets. c:\inetpub\wwwroot\CrystalWeb1\Report.rdlc 1
Error 2 The matrix ‘matrix1’ refers to an invalid DataSetName ‘DataSet2’. c:\inetpub\wwwroot\CrystalWeb1\Report.rdlc 1