If you're trying to export the report programmatically, you don't need the viewer. You just need to load the report into a ReportDocument object and then export if from there. Assuming that this is a .NET app, you can find sample code for exporting in the Crystal Reports .NET SDK section of the Developer Library (go to
http://diamond.businessobjects.com/developer/library and select the version that you're using (XI, XI r2 or XI r2 sp2). If you download the Sample Code, you'll find both ASP.NET and WinForms samples in the zip file.
(I spent some time today working on a similar issue, that's how I know the code is there in the samples!)
-Dell