Dear Community, I have started to develop a custom data extension to connect a 3rd-party application directly with the reporting services. I got all my input from this msdn article: http://msdn.microsoft.com/en-us/library/ms154655.aspx My first target was to show a simple table from the app inside a report. It seems it was easier then get some parameters for filtering working. I need the parameters inside my data reader to get it done properly. I found this topic here on the board: http://social.msdn.microsoft.com/Forums/en-US/sqlreportingservices/thread/1fb8d5b5-31f2-4a62-84c1-cb2f15217ef3 This topic helped me at least for getting the design done of a report. I can also confirm through debugging, that the parameters are collected like I need it. But when I want to preview the report I receive now this error: An error occurred during local report processing, Failed to load expression host assembly. Details: Could not load file or assembly Microsoít.Reportingservices.ProcessingCore, Version=10.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91 or one of its dependencies. Failed to grant permission to execute. (Exception from HRESULT: 0x80131418) I receive this error since I have change the parameters and added the IDbCommandAnalysis.GetParameters and generated in this method the parameters which I got from the command. So it seems to me it is related to the implementation...but it confuses me! Got someone an idea or experience with this error while preview? Is there a kind of extended logging for the visual studio, so I can get more information about the error?

This problem was related to a error in the configuration file. It's a bit strange to me, that it appeared after the implementation of the parameters. (Perhaps of internal RS stuff) I had the CodeGroup in the wrong place. I changed it and it works, but it took me a while to find the reason... (Perhaps I can help someone who got the same problem!)