A common problem with the (SSRS) reports exposed from TFS project portals, is that the report fails with an error such as;
This report requires a default or user-defined value for the report parameter 'Iteration'....
This problem only manifests (to my knowledge) in TFS servers that have been upgraded from earlier, RC or Beta versions, and whilst the problem seems quite confusing and is really annoying, the solution is simple.
The problem stems from the process templates for your projects. They have evolved over each release and the release version of TFS exposes the "MSF for Agile Software Development - v4.0" - which probably isn't set to the default on servers manifesting the above error. So your first port of call is, from Team Explorer, right click on your TFS server, select "Team foundation server settings" and then click "Process Template Manager" - find the v4.0 template in the list and make it the default.
That will solve the problem for your new projects, but how do you go about sorting out existing projects where reports aren't working. Try the following command line on your TFS server;
tfsuploadreports /s usdalweb43vm2 /p “t2 ms baseline modified” /t c:\temp\msfagile