A: 

This may sound like a generic response, but are you certain the compiled version of the report is the same as the IDE-debug version? Generally this error means that you haven't instantiated the object you're trying to use. Make sure the object has been not only declared, but actually has the data you're trying to show.

Andrew Whittington  2009-06-11 13:39:28
I'm sorry, but I really need some hand holding on this one. Where do I check that?
Ronnie Overby  2009-06-11 13:41:15
The first image is a Webpage, whereas the second is a winform control. They are definately not the same.
Jon  2009-06-11 13:45:07
Andrew is correct, this looks like you are not instantiating your ReportViewer control. Make sure that where you are creating the ReportViewer control, that you are actually creating the object.
Jon  2009-06-11 13:46:03
The first screenshot is the report manager that comes with sql server 2005. I am thinking that if the error is visible there, then this is something that is occurring before implementing the reportviewer. Am I right?
Ronnie Overby  2009-06-11 13:58:08
A: 

This will most likely be becuase the Data Source for your reports has been overwritten or the credentials have been removed/are no longer valid.

Either redeploy the Data Source or manually enter the correct details on the Report Server for the relevant Data Source.

John Sansom  2009-06-11 14:55:31
We already completely recreated and redeployed the data source as well as the reports. Where exactly do we enter these correct details?
Ronnie Overby  2009-06-11 15:17:25
It depends where you deployed the Data Source too (usuall the Data Source Folder) on the report server. Cliking the Data Source will take you to the properties page where you can validate the credentials.Also, have you enabled the OverwrtieDataSources option to True within the Project Properties in Visual Studio?
John Sansom  2009-06-11 15:45:08
Our data source is using Integrated Security and yes, that property is set to True.
Ronnie Overby  2009-06-11 15:50:18
A: 

You should also try going into the web interface and deleting the data source(s) directly from the server. Then redeploy your project. Sometimes, when deploying from Visual Studio, it won't recreate the data source because it is already there. When you redeploy, the data source will be recreated.

Mark Struzinski  2009-06-12 08:43:01
A: 

I fixed my problem by doing this:

http://serverfault.com/questions/24744/reinstall-reporting-services-2005/24811#24811

Ronnie Overby  2009-06-12 17:30:01
A: 

Hi I have re configure virtual Directory of ReportServer ... and then Give me Some Permission Related Issue ..... But Finally it's Rocking

Thanks Pritesh Gandhi. http://www.gandhipritesh.com/

Pritesh Gandhi  2010-03-22 07:02:29

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