Error 'Object Not Set to an Instance of an Object' error at report runtime

Hello,

I am creating reports for a .net web application, using Crystal Reports 10 included with Visual Studio 2005. When the reports are run within the application, they are generating error below:

Server Error in '/TestBuild' Application.

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

NullReferenceException: Object reference not set to an instance of an object.

Rhino.Reports.Views.ReportViewerPresenter.LoadDefault() in D:\Projects\Rhino\Source\Webapp\Modules\Reports\Views\ReportViewerPresenter.cs:114

Rhino.Reports.Views.ReportViewerPresenter.OnViewInitialized() in D:\Projects\Rhino\Source\Webapp\Modules\Reports\Views\ReportViewerPresenter.cs:47

Reports_ReportViewer_ReportViewer.OnInit(EventArgs e) +90

System.Web.UI.Control.InitRecursive(Control namingContainer) +333

System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +378

Now, I am not a developer, but I have been tasked with making these reports work. My hunch is it has to do with the datasource not being dynamically updated. But, I thought I would get some expert opinion on where to look first. Any help appreciated!