Here is a link that might provide you with the answer to your problem:

http://support.crystaldecisions.com/library/kbase/articles/c2011144.asp


>I have created a Crystal Report using ASP.NET that uses a data set to push the data to the report. On my test machine, everything works just fine. I copied the application to the Production environment and BOOOOM I receive the following error:
>
>Object reference not set to an instance of an object.
>
>
>[NullReferenceException: Object reference not set to an instance of an object.]
> CrystalDecisions.Web.
.get_7() +189
> CrystalDecisions.Web.CrystalReportViewer.OnInit(EventArgs e) +352
> System.Web.UI.Control.InitRecursive(Control namingContainer) +235
> System.Web.UI.Control.InitRecursive(Control namingContainer) +179
> System.Web.UI.Control.InitRecursive(Control namingContainer) +179
> System.Web.UI.Page.ProcessRequestMain() +171
>
>
>I have reinstalled Crystal Reports on the Production machines. I have verified that the CrystalReportWebFormViewer virtual directory exists on the 'Default Web Site' . The default web site was deleted originally but I recreated it thinking that its absence may be the problem. Any help is appreciated. Thanks.
>Tim