I also asked a question over at StackOverflow which I ended up answering myself. Yesterday follow up information was added, which may be of use if you have trouble with the fix.

EY Kalman says:

I have had the same problem (on several different servers). Applying SP3 and Report Viewer SP1 has helped on some of the servers, allowing the client machines to connect and download the control with no problem. However, I have had one server that, even after applying the updates, when accessing the report viewer using a client machine, it was still giving me the error. On looking into the exact URL GET request that is being sent, I discovered that it is possible to force the client machine to connect directly to the Report Server to download the control.

The user would need to enter the following url:

http://reportservername/Reports/Reserved.ReportViewerWebControl.axd?ReportSession=51bjqv45xydgos2wghu5ceza&ControlID=7617dedbf0234f89b80cad8e64431014&
Culture=2057&UICulture=9&ReportStack=1&OpType=PrintHtml

This should then pop up the required download/install prompt.

dotnettrio added (which is probably more relevant to RSinteract):

Hi,

I got this working with out removing any patches. The above patch was not working too. Finally what I did was on the IIS server install the following patch and reset / restart the IIS server. This is not for report manager application. This is for any ASP.NET Web application developed in .net3.5 using VS2008 http://www.microsoft.com/downloads/details.aspx?familyid=6AE0AA19-3E6C-474C-9D57-05B2347456B1&displaylang=en

I hope this helps anyone else with this problem.

In the last week we’ve had three clients report a problem with our December release when running on Windows Server 2003 64 bit.

Server Error in ‘/RSinteract’ Application.

Could not load file or assembly ‘Microsoft.ReportingServices.Interfaces’ or one of its dependencies. An attempt was made to load a program with an incorrect format.
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.BadImageFormatException: Could not load file or assembly ‘Microsoft.ReportingServices.Interfaces’ or one of its dependencies. An attempt was made to load a program with an incorrect format.

This new error has popped up since Microsoft released the update KB956391.

The update is for a vulnerability in the GDI+ DLL which allowed a malicious user to execute code on the client machine (good old! – ed). The fix uses ActiveX Killbits which is a setting that Internet Explorer checks for each ActiveX control. If the Killbits are set, IE refuses to load the control.

The update set the Killbits for the version of the RS Client Print ActiveX control which is used by the version 8.0.0.0 of the ReportViewer which is referenced by RSinteract (and Report Manager). Thus the printing will not work in either.

To fix Report Manager you need to apply the ReportViewer SP1 patch and the Security Update for SQL Server SP2 (KB954606). Once this is working again you can fix RSinteract.

To fix RSinteract you need to apply another Security Update for SQL Server SP2 (KB954607).

Let us know if this fix doesn’t work for you.