Hi, thanks but in our configuration the reporting services resides on the DB server.
The error in detail was 404.15. We found that the problem was in the length of the get call for exporting the report which was inconsistent with the default settings of the ASP.NET web application. We solved it by making the maximum url length explicit in the web.config.
<system.webServer>
<security>
<requestFiltering>
<requestLimits maxQueryString="3000" maxUrl="1000"/>
</requestFiltering>
</security>
</system.webServer>
Bye