Somebody just reported on the RS mailing list that SQL Server 2005 Express killed his Reporting Services. It might not happen to everybody but it's good to know that this could be an issue. Here is the text of the email:
Microsoft has posted a release of SQL Server 2005 Express Beta (http://lab.msdn.microsoft.com/express/sql/) .
Part of the install is the .NET Framework 2.0. But I install it, the Reporting Services instance on the same system gets corrupted. When I try to go to the http://localhost/reports, I get the error "System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.InvalidOperationException: Method ReportingService.SetExecutionOptions can not be reflected. ---> System.IO.FileLoadException: Unknown error - HRESULT 0x80131047"
Restarting the service did not help. Uninstalling Framework 2.0 resulted in Reporting Services having a corrupted keyset. After restoring the keys using rskeymgmt fixed the problem.