Xml and Web Services Datasources from c#

Hi,

I had a set of reports created with Crystal Reports 2011; each one is using a 'Xml and Web Service' datasource that is binded to a local XML file.  They are working well when you do a preview from Crystal Reports application.

The problem is when I try to export these reports from a C# application to a PDF file. Each time I try it I get this error:

     No es posible cargar la información de la base de datos.

     Error en el archivo stage {90F39511-918D-469A-A865-148769735C22}.rpt:

     No se pudo cargar la información de la base de datos.

In english is something like this:

     It's not possible to load the information from the database.

     Error on file stage {90F39511-918D-469A-A865-148769735C22}.rpt:

     Information from database could not be loaded.

The code I'm using is something like that:

     ReportDocument rpt = new ReportDocument();

     rpt.Load@"c:\myreport.rpt");

     rpt.ExportToDisk(ExportFormatType.PortableDocFormat, @"c:\test.pdf");

I have been using this kind of code without problems with reports with ADO.NET datasources but I can make it work with this 'Xml and Web Service' datasources, any ideas?

Thanks for you help.