Report Source problem

Dear Friends,

I have created a crystal report as rptInvoice. I have added a dataset dsInvoice as the database fields in report.

Now I have created an form that contains crystalrReportViewer1 in it. Here I am writing the code in form_load(). But when I want to load the report when running the project it says INVALID REPORT SOURCE.
Can anyone help me?

The code in form_load() is as follows:

DataSet dsInvoice = collectDS();
rptInvoice doc = new rptInvoice();
doc.SetDataSource(dsInvoice);
crystalReportViewer1.ReportSource = doc;

Here collectDS() is returning the dataset with datatable.

If u have any clu please help me...

Rajib